Right now for me, the easiest is a 12-bar with A7, D7, E7 as shown by Rigk Sauer from RISA ukulele, here in his ukulele blues workshop:
https://www.youtube.com/watch?v=13FPL5cYMGM
Another thing I've fooled around with is tuning the uke as
G-C-E-G
which with low-g as the 4th string gives me a C-major chord and a octave-G on the 1st string, and then you can easily do blues in C either with a guitar slide or by doing a flat barre chord, and if you want the bomba-dida on beats 2 & 4 as you are chunking, it's easy to add the Maj-7th to the flat chord shape
so the 1-4-5 or I-IV-V is open-4th fret-5th fret
I do not think it is possible to get simpler than this...
Maybe 9th and 13th chords might be simpler to finger in this tuning but I have not tried it yet...
Also with a re-tune an open F, G or or D chord is not far off, and easy to play with similar progressions...
I saw a YT video of a guy doing something like this and re-tuning mid song to change the open chord, but he had friction tuners so it was do-able inside of a single beat, but I can not remember who did it and I did not save the link...
lots of FUN with BLUES on uke!