Joomla 4.2 expert customize website after migration

Website does not migrate to 4.x version or it does migrate but with many errors. I tried to solve that one, but after the last one was solved I got 30 new error messages. I think I'm using extensions (or old discontinued extensions) that are not (yet) compatible with joomla 4.x. Before migration I disabled everything that pre-check indicated as a possible problem, but that didn't help.

I'm looking for someone with knowledge of joomla who - together with me - can look into transferring website to 4.x version.

The picking garden will open again at the end of May. I would like to have the website working properly again before then.

Website can be accessed via laptop, so update could be done from any location with WiFi.

If migration succeeds, it can be done in a few hours. However, I've been working on it for about a week (unsuccessfully).

As a thank you, you can come and pick a beautiful bunch of flowers during the picking season.