I'm afraid it's a similar story with WiiM and Sonos.
I disabled all the DSP but there's still a gap between tracks.
Displayed album art, metadata (track title, album and albumartist), track progress and track technical details.
2835; 9 Profile - WiiM, useragent=|Linux/4.9.113
2836; 10 Profile - WiiM, useragent=|Linux/4.9.113
2857; 11 Activate - WiiM Pro-60F6:http-get:*:audio/wav:DLNA.ORG_PN=LPCM,http-get:*:audio/x-wav:DLNA.ORG_PN=LPCM,http-get:*:audio/mpeg:DLNA.ORG_PN=MP3,http-get:*:audio/mpeg:DLNA.ORG_PN=MP3X,http-get:*:audio/x-ms-wma:DLNA.ORG_PN=WMABASE,http-get:*:audio/x-ms-wma:DLNA.ORG_PN=WMAFULL,http-get:*:audio/x-ms-wma:DLNA.ORG_PN=WMAPRO,http-get:*:audio/mpeg:DLNA.ORG_PN=MP2_MPS,http-get:*:audio/mp3:*,http-get:*:audio/wma:*,http-get:*:audio/mpeg:*,http-get:*:audio/vnd.dlna.adts:DLNA.ORG_PN=AAC_ADTS,http-get:*:audio/vnd.dlna.adts:DLNA.ORG_PN=AAC_ADTS_320,http-get:*:audio/m4a:DLNA.ORG_PN=AAC_ISO,http-get:*:audio/aac:DLNA.ORG_PN=AAC_ISO,http-get:*:audio/ac3:DLNA.ORG_PN=AC3,http-get:*:audio/ogg:*,http-get:*:audio/ape:*,http-get:*:audio/x-ape:*,http-get:*:audio/flac:*
9699; 12 Play - D:\MusicBee Test\music\Stanton Warriors\2001 - The Stanton Session\01.01.flac (http://192.168.0.12:49382/files/C50AB82914AE234Dp.flac)
9987; 13 Profile - Generic Device, useragent=Lavf/58.45.100
9997; 14 GetFile[1] 192.168.0.12 - GET D:\MusicBee Test\music\Stanton Warriors\2001 - The Stanton Session\01.01.flac to 192.168.0.137
9998; 15 Profile - Generic Device, useragent=Lavf/58.45.100
10335; 16 GetFile[1] - exit=0, playtime=336
10349; 17 StateTimer - Playing,old=Stopped
10368; 18 SetNextAVTransportURI - Success - http://192.168.0.12:49382/files/0C2D7A04A970C9EEp.flac
31551; 19 Profile - Generic Device, useragent=Lavf/58.45.100
31557; 20 GetFile[2] 192.168.0.12 - GET D:\MusicBee Test\music\Stanton Warriors\2001 - The Stanton Session\01.02.flac to 192.168.0.137
31557; 21 Profile - Generic Device, useragent=Lavf/58.45.100
34473; 22 GetFile[2] - exit=0, playtime=2914
66856; 23 Seek - goto=0
66864; 24 Seek - pos=0
66899; 25 SetNextAVTransportURI - Success - http://192.168.0.12:49382/files/C0A8B86B104C228Fp.flac
2321; 8 ProcessMessage 192.168.0.100 - device 'uuid:RINCON_000E58C5095001400_MR:192.168.0.100 - Sonos Play:1 - RINCON_000E58C5095001400',valid=True
2324; 9 Profile - Sonos, useragent=|Linux UPnP/1.0 Sonos/83.1-61240 (ZPS1)
2325; 10 Profile - Sonos, useragent=|Linux UPnP/1.0 Sonos/83.1-61240 (ZPS1)
2352; 11 Activate - 192.168.0.100 - Sonos Play:1 - RINCON_000E58C5095001400:http-get:*:audio/mp3:*,x-file-cifs:*:audio/mp3:*,http-get:*:audio/mp4:*,x-file-cifs:*:audio/mp4:*,http-get:*:audio/x-m4a:*,x-file-cifs:*:audio/x-m4a:*,http-get:*:audio/mpeg:*,x-file-cifs:*:audio/mpeg:*,http-get:*:audio/mpegurl:*,x-file-cifs:*:audio/mpegurl:*,file:*:audio/mpegurl:*,http-get:*:audio/x-mpegurl:*,x-file-cifs:*:audio/x-mpegurl:*,http-get:*:application/x-mpegurl:*,x-file-cifs:*:application/x-mpegurl:*,http-get:*:application/vnd.apple.mpegurl:*,x-file-cifs:*:application/vnd.apple.mpegurl:*,http-get:*:application/dash+xml:*,x-file-cifs:*:application/dash+xml:*,http-get:*:audio/mpeg3:*,x-file-cifs:*:audio/mpeg3:*,http-get:*:audio/wav:*,x-file-cifs:*:audio/wav:*,http-get:*:audio/x-wav:*,x-file-cifs:*:audio/x-wav:*,http-get:*:audio/wma:*,x-file-cifs:*:audio/wma:*,http-get:*:audio/x-ms-wma:*,x-file-cifs:*:audio/x-ms-wma:*,http-get:*:audio/aiff:*,x-file-cifs:*:audio/aiff:*,http-get:*:audio/x-aiff:*,x-file-cifs:*:audio/x-aiff:*,http-get:*:audio/flac:*,x-file-cifs:*:audio/flac:*,http-get:*:application/ogg:*,x-file-cifs:*:application/ogg:*,http-get:*:audio/ogg:*,x-file-cifs:*:audio/ogg:*,sonos.com-mms:*:audio/x-ms-wma:*,sonos.com-http:*:audio/mp3:*,sonos.com-http:*:audio/mpeg:*,sonos.com-http:*:audio/mpeg3:*,sonos.com-http:*:audio/wma:*,sonos.com-http:*:audio/mp4:*,sonos.com-http:*:audio/x-m4a:*,sonos.com-http:*:audio/wav:*,sonos.com-http:*:audio/aiff:*,sonos.com-http:*:audio/flac:*,sonos.com-http:*:application/ogg:*,sonos.com-http:*:application/x-mpegURL:*,sonos.com-http:*:application/dash+xml:*,sonos.com-spotify:*:audio/x-spotify:*,sonos.com-rtrecent:*:audio/x-sonos-recent:*,x-rincon:*:*:*,x-rincon-mp3radio:*:*:*,x-rincon-playlist:*:*:*,x-rincon-queue:*:*:*,x-rincon-stream:*:*:*,x-sonosapi-stream:*:*:*,x-sonosapi-hls:*:*:*,x-sonosapi-hls-static:*:*:*,x-sonosapi-radio:*:audio/x-sonosapi-radio:*,x-rincon-cpcontainer:*:*:*,
4658; 12 Play - D:\MusicBee Test\music\Stanton Warriors\2001 - The Stanton Session\01.01.flac (http://192.168.0.12:49382/files/C50AB82914AE234Dp.flac)
4777; 13 Profile - Sonos, useragent=Linux UPnP/1.0 Sonos/83.1-61240 (ZPS1)
4787; 14 GetFile[1] 192.168.0.12 - GET D:\MusicBee Test\music\Stanton Warriors\2001 - The Stanton Session\01.01.flac to 192.168.0.100
4788; 15 Profile - Sonos, useragent=Linux UPnP/1.0 Sonos/83.1-61240 (ZPS1)
5279; 16 StateTimer - Playing,old=Stopped
5893; 17 SetNextAVTransportURI - Success - http://192.168.0.12:49382/files/0C2D7A04A970C9EEp.flac
8167; 18 GetFile[1] - exit=0, playtime=3376
48529; 19 Profile - Sonos, useragent=Linux UPnP/1.0 Sonos/83.1-61240 (ZPS1)
48535; 20 GetFile[2] 192.168.0.12 - GET D:\MusicBee Test\music\Stanton Warriors\2001 - The Stanton Session\01.02.flac to 192.168.0.100
48536; 21 Profile - Sonos, useragent=Linux UPnP/1.0 Sonos/83.1-61240 (ZPS1)
60440; 22 Seek - goto=0
60546; 23 Seek - pos=0
60559; 24 GetFile[2] - exit=10054, playtime=12023
60600; 25 Profile - Sonos, useragent=Linux UPnP/1.0 Sonos/83.1-61240 (ZPS1)
60600; 26 GetFile[3] 192.168.0.12 - GET D:\MusicBee Test\music\Stanton Warriors\2001 - The Stanton Session\01.02.flac to 192.168.0.100
60601; 27 Profile - Sonos, useragent=Linux UPnP/1.0 Sonos/83.1-61240 (ZPS1)
60716; 28 GetFile[3] - exit=10054, playtime=114
60720; 29 Profile - Sonos, useragent=Linux UPnP/1.0 Sonos/83.1-61240 (ZPS1)
60722; 30 GetFile[4] 192.168.0.12 - GET D:\MusicBee Test\music\Stanton Warriors\2001 - The Stanton Session\01.02.flac to 192.168.0.100
60724; 31 GetFile - range=bytes 9043968-34723562/34723563
60724; 32 Profile - Sonos, useragent=Linux UPnP/1.0 Sonos/83.1-61240 (ZPS1)
62121; 33 SetNextAVTransportURI - Success - http://192.168.0.12:49382/files/C0A8B86B104C228Fp.flac
64904; 34 GetFile[4] - exit=10054, playtime=4179