Thirding it except I do it from Emacs. Three side-by-side pane with left / common ancestor / right and then below the merge result. By default it's not like that but then it's Emacs so anything is doable. I hacked some elisp code a great many years ago and I've been using it ever since.
No matter the tool, merges should always be presented like that. It's the only presentation that makes sense.
The extensibility provided with Emacs Lisp has been helpful for hacking together my own Git/Jujutsu plugin. I tried to model it over lazygit/lazyjj although magit has been incredible to use and hard to depart from.
I think you need to enable 3 way merge by default in git's configuration, and both smerge (minor mode for solving conflicts) and ediff (major mode that encompass diff and patch) will pick it up. In the case of the latter you will have 4 panes, one for version A, another for version B, a third for the result C, and the last is the common ancestor of A and B.
Addendum:
I've since long disabled it. A and B changes are enough for me, especially as I rebase instead of merging.
No matter the tool, merges should always be presented like that. It's the only presentation that makes sense.