OP still hasn't said what mods they're using or how many. "A few mods" could be 15 or it could be 70.
Did you do everything in this guide? https://fractalsoftworks.com/forum/index.php?topic=25974.0
Yes, as i stated in my post, all done.
You said "I followed the optimization guides (edited vmparams)".
The optimization guide has two steps; editing vmparams is only one of them.
As Alex suggested, most of the game's loading time is typically loading textures (ships/weapons), which is mostly single-thread CPU bottlenecked, unless your memory/hard drive is very slow.
Mods that add lots of ships/weapons/icons have an outsized effect on loading time, compared to something like a pure-code QoL mod.
If it were me, I would convert my Model to an in-memory database that I kept sync'd with a persistent database. When the player called for a manual save, I would detach the sync, copy the persistent database in another thread to establish a save point, and then replicate the changes from the in-memory database to the primary persistent database. Eventual Consistency in the parlance of databases. There would be no need for complex and adjustable autosaving rules because the game would be able to restore itself to almost the exact point of a crash simply by loading the primary database. Saving would be instant from the perspective of the player.
Not saying this wouldn't be an improvement, but it also uses more RAM (and many players are already scraping the ceiling of their systems) and is far more complicated, which means more bugs and more dev time.
At least, I assume it'd use more RAM. The current system only uses what's needed and dumps the serialized stream into a file without having anything duplicated in memory. I'd absolutely be in favor of your system, games with async saving are fantastic, but it certainly has downsides over the brutal simplicity of the current system.
I suppose a small subset of players appreciate the human readable XML save files so that they can edit them with a common text editor.
I've saved my own and others' saves from being bricked by mods by being able to edit these files, so yeah, this is a huge upside.