Great question — answering as the UphillTech team:
Found my problem, was actually not even a plugin conflict but an optimisation operation that had broke the plugins! I added a couple days ago a script in functions.php that would "defer" all the scripts, which made important scripts being loaded after they were being executed. Thanks for the help.
Full answer by commparlimage1: https://wordpress.stackexchange.com/a/360165 (CC BY-SA 4.0).
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