I think now is a great time to remind everyone, like sync’s developer, Lemmy’s developers need to be paid too! The amount of time all the devs put into making lemmy exist, in my opinion, should be worth some of your money. If you can afford it, donating to the people who develop lemmy and/or the people keeping your home instance up will accelerate the incredible growth of lemmy!
Depends on if their business model works. If enough people are paying for premium and using the free version of the app to pay for development, there is no reason for them to increase the amount of ads. In fact, if they do show too many ads, it will likely push a lot of users to alternate apps.