Not sure how many I’ll ever do but the wife wants doors on an old free standing cabinet and I’ve determined that concealed hinges and shaker style doors are the way to go. Is the Kreg jig that important or can I get away with the drill guide and a 35mm forstner bit?

I've used the Kreg jig and it works great. The setback from the door edge would probably be tricky without a drill press/fence or a jig.

The setback is crucial. I’d go with the Kreg jig.

some very important thing you have to go by.
1. overlay how much does the door overhang the frame? 1/2 inch is very common if you have an odd size chances are the mounting plates which are different height's will not fit.

2. set back from the edge is another critical measurement, for most of mine I do 4 mm but all that can vary and you can get in a situation where the door will rub on the hardware.

3 alignment of the hinge is critical if it's off just a little the door will bind as the hinges are working against each other and the door wont shut.

4. mounting plates there are so many different ones and they can mount to the main box of the face frame.

in my cabinet shop I have an automatic boring and insertion machine I also have a special pneumatic predrill for the face frames.
as you can see lots of variables, right now there is a huge shortage of hinges and drawer slides I have had thousands on order since June.

for 1/2 inch overlay I use blum hinges Manufacturer Number:73B3580

with a face frame plate 175L6030.21

4 mm set back to edge of hole.

https://www.blum.com/us/en/

If you haven't installed these hinges before then getting the KREG jig would probably be a good move.

Was hoping not to have another single purpose jig but looks like I’d be dumber than usual to freehand it. Thanks again guys.

if you weren't so far away I would bore you the pattern with my omal machine and send it to you, so you could use it as a template. probably cost more to ship it from Oregon then the jig would cost.

Thanks for the offer! Stroke of luck yesterday, there was a Kreg jig in a ripped up package that got clearanced for $5 so I snagged it.