jviola wrote: What would you choose?
That's a good question.
Let's look at the camera choice: The PtzOptics30X camera is $1799 whereas the 20X camera is $1699. The 20X provides the zoom range needed in the chapel.
Power for the camera: The camera accepts POE so I would use one CAT cable for power and IP connection.
Choice of PTZ Controller: The Rs232 version is $299, the IP version is $650, and a really GOOD free IP touch program
https://www.pantiltzoom.cam/ runs on any iOS or Android device. Something to know about is the minimum step size for Pan/Tilt movements. The free touch program has the ability to make the smallest possible step whereas the RS232 Controller step size is about 4 times larger.
Choice of Switcher: The switcher needs to have a Preview output, Program Output, Scaler on at least one input, easy overlays, and several easily adjustable analog audio inputs, and a simple to use control surface. Each model of the ATEM series has some deficiency whereas the Roland V-1HDPlus
https://www.amazon.com/dp/B08KSJGCG8/ meets all criteria - but it cost a bit more at $1200.
Sending HD video over SDI: Using your existing RG6 coax - you need to change the coax connectors to BNC connectors rated for 3Ghz operation and just plug the cable into the camera SDI output. Buying a SDI to HDMI converter
https://www.amazon.com/dp/B01FSQYH5O/ gets the signal back into HDMI format for the Switcher.
Sending HD video over CAT5e/6 cable: Using your second existing CAT cable, you need to purchase a pair is HdBaseT adapters
https://www.amazon.com/dp/B079M2BFKD// using one adapter at each end of the CAT cable. The nice thing about HdBaseT is you can transfer the video AND the IR signal AND the RS232 signals. Having the IR remote control available is a good backup for PTZ control and some people may actually prefer it. HAving the RS232 available lets you use a lower cost or existing PTZ Controller.
My choices would be.
Camera: 20X to save $300 on three cameras . These cameras can also be purchased used on eBay for $1000-$1500each.
PTZ Controller: I very much prefer the free iOS program running on an iPad, but others may prefer a more traditional control surface of the RS232 or IP version.
Switcher: The Roland V-1HD+ is my choice. Compared to the ATEM Switchers it has more of the needed features (especially audio features) and a better control surface.
Sending HD Video from camera: I prefer using HdBaseT because you get the added benefit of having the IR and RS232 signals available. If you don't care about IR and RS232 then SDI is a good choice. Having used SDI, HdBaseT, and wireless, my personal subjective judgement is HdBaseT is also the most robust.