if you have the newest version of java installed and everything else up to date and you tried redownloading and installing, i do not know how to help you, sorry. a few other players have problems with saving and loading...it is engine related and not much i can do about it because the game engine doesn't really get support anymore, but i don't think i have encountered anyone that has to wait 10+ minutes to load a save. don't forget that this game is quite popular...it has over 50 000 downloads here alone on itch.io. not to mention the download on patreon and other places...
...that means many have played and completed it. completed it with all church scenes and until day 84. you think that everyone who plays this game experiences the same issues as you do, but that is not the case. i think in this case it is a connection between the engine and the drivers and operating system that is installed. but, of course, i can't say for sure.