I have used a traditional sit i.n kayak which is probably môre stable since you have a lot of weight below waterline.

Sit on tops can be stable enough to standup in but will be 100 pounds or more.

Inflatable kayaks from Sea Eagle are touted to be extremely stable and they offer a six month trial period.

Another option is Wavewalk. They are easy to board from a bank, extremely stable, and great for anyone with back issues since you sit upright on a “saddle” style bench. I used one once and could easily stand up in it. Only available online through wavewalk.com.

Hope this is helpful –
Ralph
Hollis, NH

My balance makes it difficult to cover much area on the court. Do you think it would help if there was a longer handle version of a pickleball paddle?
Ralph
Hollis, NH