Top on HW

My suggestion:
Premier League - 8 players in a round-robin format. 5th-6th place participate in a qualifying tournament with the 3rd-4th places from the lower league, and 7th-8th place are eliminated.

Non-Premier League - 16 players in a Swiss-system tournament.
1st-2nd place advance directly, 3rd-4th place compete in a best-of-two or round-robin playoff.
13th-16th place are eliminated, and 9th-12th place participate in a qualifying tournament (I'll explain why so many: there are many strong new players, and some of the veterans may have lost interest or have limited time). In the end, there are even slightly more than 10+10 players, but this allows for more rotation. IMO, qualifying matches should be mandatory, as they provide an additional chance and an additional filter.
(This results in 7 games in each league)