Save a botched 2 stage carve - type of fill?

Is there a recommended type/brand of fill that people use? I just spent way too long at Michael’s & Joanns looking for options.

Michaels had a Poly Resin that was clear, but didn’t have any dye/tints. And from what I read on here, Epoxy Resin is better as it doesn’t shrink. I was most intrigued by E6000 Allure . Kinda reminded me of those 3D paints you used as a kid to draw designs on t-shirts and it made a thick/flexible design. My concern was that it wouldn’t be fluid enough to fill the carve since it’s made to stand up and be 3D

Joanns only had acrylic paint…

Am I going to the wrong stores? Or do the better carve filler products only exist online?

In my mind, I’m not looking to do a over-pour type application, but was thinking I could find something like these little bottles with tips (below). And then put the thick paint/resin/epoxy/ihavenoidea and carefully pipe it into the carve.

If you get yours online, where it is that people buy and what do they buy for this sort of application?