I bought this last year and it's come very handy, Sure a more expensive piece may offer different options, but this gets me centered on an edge perfectly. I use dowel points to mark the opposite side for a perfect fit.

https://www.amazon.com/gp/product/B08R9B8L6G/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I recently bought this corner jig for an entertainment hutch I built...no screws. Just glue and 3/8" dowels...and I like the look.

https://www.amazon.com/gp/product/B07XH3Y8DV/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1