New Teams starts exactly once with Hotfix 4, after that nothing happens when you try to start teams. I tested with 5 users under Windows 10 (without Citrix) and Windows Server 2019 (Citrix VDA 2311). The following can be found in the event log after each start attempt:
Name of the faulty application: ms-teams.exe, version: 24102.2223.2870.9480, timestamp: 0x663ea2a9
Name of the faulty module: ucrtbase.dll, version: 10.0.17763.1490, timestamp: 0x48ac8393
Exception code: 0xc0000409
Fehleroffset: 0x000000000006e77e
ID of the faulty process: 0x2a88
Start time of the faulty application: 0x01dab651130fd0bf
Path of the faulty application: C:\Program Files\WindowsApps\MSTeams_24102.2223.2870.9480_x64__8wekyb3d8bbwe\ms-teams.exe
Path of the faulty module: C:\WINDOWS\System32\ucrtbase.dll
Berichtskennung: 0b52ccdb-8328-4520-8797-8ef75f701717
Full name of the corrupted package: MSTeams_24102.2223.2870.9480_x64__8wekyb3d8bbwe
Application ID that is relative to the faulty package: MSTeams
Hotfix 3 didn't have this problem.