Gmail accessed by third party – deleting important emails – saw one disappear an hour or two ago need recovered

I am in a custody dispute and my ex has in the past verified used spyware – very resourceful. I noticed on multiple occasions that key emails were deleted – a few times I managed to recover them and they were basically all important to one person only.

I was just looking at an important email a few hours ago, clicked away from it and returned 30 seconds or less later to find it gone and not in any folders, I checked trash spam etc, and nothing. I then went to https://support.google.com/mail/workflow/9317561?visit_id=637158719326521936-227949149&rd=1 (Gmail message recovery tool) and made request for recovery. Returned message to check my email – if found it would reappear within 20 hours. I remembered that one time before it had taken a few hours, so checked back and still nothing, so I tried again. this time it returned "were sorry no messages to recover, tried again and it returned "we see you have a recovery in progress – continue or start new" i cant recall but it returned various messages each time, one of which was "something wrong, escalate with google – only came up once – now returning nothing or "we see a search is requested, continue or new"

I think google can search – ie with a person doing it on their end for 30 days – not sure how to escalate though. And yes I have changed PWD multiple times – HELP