Uiua
Part 1:
&fras "day3/input.txt" /+≡/×≡⋕≡↘1regex "mul\\((\\d+),(\\d+)\\)"
Part 2:
Filter ← ⍜⊜∘≡⋅""⊸⦷°□ .&fras "day3/input.txt" ∧Filter♭regex"don't\\(\\)?(.*?)(?:do\\(\\)|$)" /+≡/×≡⋕≡↘1regex "mul\\((\\d+),(\\d+)\\)"
I would take:
Uiua
Part 1:
Part 2: