Wheni would launch the trainer it would have a pop-up that said "you need to have .Net Core 3.1 or later. Do you want to install it?" and give an option for yes or no. No cancels the launch and yes takes you to download page for ".NET Runtime 3.1.22" which i can't find the exac't page link since i can't replecate the issue since I've fixed it but when I instead installed ".NET Desktop Runtime 3.1.22" it worked.
Someone would have to give a save file with max health to the trainer maker for it to account for the fully upgraded health. I imagine the Memory marker for max health changes as you increase your max health so the option was created when the save used had the base max health.
The save file I posted the other day has max health with the apples you find throughout the game. Health given by gear would make it more, but I don't have the end game gear yet.
Do you have the newest trainer we uploaded?
Steam had an update for the game