Disc brake caliper mounting.

Hi all,

I've got a bike that came with mechanical disk brakes and what seems like standard post mount bolt pattern on the frame and IS on the fork.

I brought an L-Twoo GR9 groupset to upgrade the bike to a 1x and add hydraulic brakes (no matter the adjustment and attempts from mechanics the braking has been woeful and I'm on the heavier side).

The GR9 calipers seem to have slightly off spacing from post mount and and also use a 1mm smaller bolt size.

It doesn't quite seem like a flat mount caliper however.

What adaptor do I need to get the new brake calipers in? Thank you!