Disabled by WIndows Updates

I'm new to Bitdefender. My laptop has just installed a Windows 11 update and restarted. Following the update, Windows Security was happily reporting no issues, but looking in more detail I found there was no anti-virus protection or web protection running. Bitdefender had been disabled and I had to logon to restart it. My previous anti-virus application (TotalAV) was similarly affected, although to a worse level (it needed a re-install each time - so I binned it after just 4 days and started with Bitdefender). I get the impression that WIndows, specifically Microsoft Defender is fighting against other anti-virus software, particularly during an update. Do other people have similar experiences, and is there anyway of ensuring that Bitdefender is not turned off by a Windows update?

As an aside: my laptop has also become much slower to boot-up since I upgraded from WIndows 10 to 11 which I am now putting down to a 'war' between Microsoft Defender and any other installed anti-virus applications.