@yagmurkast The world of Isla Paradiso is so broken as to run poorly on any system. The workarounds are to use an edited version of the world or to edit it yourself. Please see the first post of this thread for more details:
https://forums.thesims.com/en_US/discussion/811253/removing-ip-lag
Please keep in mind the Scott family isn't broken; the problem is the wife is pregnant and doesn't have maternity leave, so she keeps trying to spin into a work outfit that's invalid for pregnancy. The fix for this is to use a mod to give her a couple days off work, or play her for a moment and have her quit her job.
Another helpful tool is this mod, which players report cuts down on lag to a significant extent, although it doesn't fix every cause of lag:
https://modthesims.info/d/665907/reduce-remove-lag-caused-by-houseboats.html
It's worth noting that none of these issues would follow you into a save in a different world, even with Island Paradise installed. So you could instead choose to play somewhere else and skip all the workarounds.