Regarding ads, exoclick is a good adult ad network I can recommend at least from the advertiser perspective (have not tried it from the webmaster perspective). Juicy is also good, but less flexible. In-house ads is also a great option, and there are some open source packages that you could use so you donāt have to write such a system yourself (some even can show stats to advertisers), though the management time concern is fair.
I can sympathize with cloud hosting being very expensive. If the load is relatively predictable, than colo/dedicated servers can be a tremendous cost saving. (You can install proxmox and get basically your own private cloud that you can still run VMs inside of.) High availability is trickier, but possible with a router and two machines. Downside is colo can be kind of a pain to set up initially since it requires negotiating deals and shopping around; plus I donāt envy anyone buying RAM right now! But 1U/1A colo can be had for $60-80/mo each including bandwidth. For equipment, used enterprise gear (was) cheap on serverpartdeals/servermonkey etc. For newer gear, ServeTheHome has some good server building/processor reviews that are worth checking out ā newer generation processors can do crazy amounts of CPU within 1 amp (ex: an Epyc 4464p gets you 12 cores (24 dedicated threads āvcpuā in cloud parlance) with a total 47k passmark score at ~$500 upfront purchase). So for a single colo server with new equipment, thatās $2-3k upfront investment and <$100/month ongoing for colo vs the equivalent āGeneral Purposeā (dedicated thread) VMs (16+8vcpu for 24 thread) runs $756/month on digital ocean. (Or used equipment is much less cost if less performance is required) So basically you make your money back in a few months, because cloud markups are crazy high. Or pay nothing upfront and higher monthly to rent dedicated servers and still pay less than cloud.
Also for static content CDN, I really like Bunny.
Anyway, unsolicited suggestions but I saw this and thought it might be useful info.