Is TechKeys' key not in DCS profile? I don't think it would look good together with OEM profile.
I second the recommendation for Leopold keycaps. They are some of the best quality caps I have seen: PBT (including the space bar), thick walled, Cherry profile, sharp edges, nice texture.
The sets come with both stepped and non-stepped Caps Lock.
I use the stepped Caps Lock on a Ducky keyboard with centred Caps Lock stem. It works well.
The top surface of the Caps Lock is the same size as the Tab key above though, not as small as on Cherry's keyboards.
You could get a TKL keyboard with cheaper keycaps for relatively little money these days. Just make sure that the size of the keycaps match. The key sizes that vary the most are on the bottom row: the keys to the left and right of space bar. They should all be the same size: 1.25 × wide a regular key.
Edit:
Or... get a Leopold TKL keyboard from the start. They have them for preorder at MechanicalKeyboards.com:
https://mechanicalkeyboards.com/shop/index.php?l=product_detail&p=1564They don't seem to come with the stepped Caps Lock key, but you could perhaps buy the matching stepped key from someone on this board who had bought the individual set. That could even be cheaper.
And yes, we are talking only ANSI here. Leopold does not make keyboards in other language-specific layouts that I am aware of. I use blank keys (non-printed) myself, with an Enter key from another board.