Firing Google Ad Agency and moving in-house with AI suggestions...

Just saw a post here that mirrors what my work's situation is but I am hoping it's a slightly different outcome to that one.

I just began as the marketing/social media specialist at a veterinary clinic with admittedly minimal google ads experience. They want to boost their marketing and the agency we use is tailored towards vet clinic but I don't know that I believe they are truly a useful agency.

About the ads under the agency:

-They run their own account that we have no access to (search ads only)

-They are using call rail to track calls and form submissions as primary conversions. The form submissions almost never amount to booked appointments (which is the only true conversion we need) and calls are a bit more successful.

-Per their reports: $6.58 avg CPC, 75 conversions/mo for last few months on avg, $32.89 cost per conversion

-$2,500/mo budget on ads and $300/mo spend on the agency

-However I manually went through their "conversions" and we typically get roughly 3-10 new clients ACTUALLY booking appointments per month despite their conversions being inflated as there's no true metric on what leads to booked appointments.

-They only use one landing page on a subdomain that looks clunky and frankly not good with wayyy too much info on the page and lack typical landing page things such as social proof...

So yes I turned to AI for analysis and suggestions and initially was hoping to work with the agency to improve what they already have going on. Everything in terms of research I have done (not just using AI) led me to this plan:

-Move Ads in house, build out landing pages per campaign

-Utilize GTM + GA4

-Implement an actual book now button that is trackable (fires a conversion when an appointment is booked using a booking widget not just a form submission with contact details) on our landing pages

-Utilize callrail still but implement DNI rather than static to see what is working

-Launch with minimal campaigns and ad groups with 2 RSA's each to learn from performance then grow (agency currently has 3 campaigns targeting 3 different services with many ad groups within)

-Same monthly budget

I expect our conversion "rate" to drop a lot, since we will be more accurately tracking actual conversions now but I am still apprehensive given lack of experience so any thoughts on if this sounds like a terrible idea is appreciated.