i have no idea how successful a subscription model might be, but i suspect it might be a turn-off even for those who would not want to subscribe
personally i’m fine with ads as long as they are in a sidebar, or there’s an option to hide them, or, if combined with the results, clearly marked and wrapped in a div with a css class so one can inject the necessary css to hide them 
if you’re using Firefox (or Chrome i’m pretty sure), see Skip Redirect and ClearURLs (or ClearURLs for uBO if you’re using uBO)
regarding Coil, personally i wouldn’t get near that with a 99 ft. pole - for starters, they’re breaking AMO rules by linking to their privacy policy rather than displaying in full on AMO and their “privacy” policy is, if i may be blunt, crap - it is also not immediately clear to me whether one has a choice of what companies one wishes to fund
registering can be completely anonymous - for example i use a VPN that requires zero personal information and accepts cryptocurrencies - customers are identified via the sharing of a cryptographic key