@Lazarou Speaking of tradition.
Upper house reform might be an interesting idea. For instance, only a part of an elected house could be replaced in any one election, and / or they could have staggered terms to better check and balance the lower house. It would help avoid the sort of "high stakes" battles which populists thrive on. Could also be an area to experiment with a different voting system.
Courts could have a bigger role for enforcing a set of rules which the government shouldn't violate. If it's the advisory role of the Lords, maybe advisory expert committees? I dunno.
While the Lords are touted as a "check and balance", they rubber-stamped a lot under Johnson.