With Nextcloud 24 the performance was improved (Video “Nextcloud announcement & live Q&A”). I think that you can already feel something. But i think that does not really solve your problem. But the performance advantages alone make an upgrade worthwhile.
if your hardware is not good, you will never get a fast instance. If you still want to get the best out of what you have now, you definitely want to upgrade to the last minor release of 23, or to 24, there have been a lot of efforts in performance. You could also experiment with disabling your apps one by one to see if any of those makes an impact.