Sometimes the clues come easy, sometimes they don't... Some of these were unexpectedly tricky to clue. Here are my explanations for the perplexed & curious:
ACROSS
1A. cook = FRY, around anag. ZEN.
4A. firearm = REVOLVER; subtract rights = Rs.
9A. hidden in beneaTH UMBrella.
10A. reversal of box office = BO + against = V (versus) + debts = IOUS.
11A. managed = RAN, to fire = SACK.
12A. tell porkies = LIE, around English = E + good = G.
13A. mental blocks = INHIBITIONS, switching trendy = IN for no-longer = EX.
18A. imprecise = UNCLEAR, incomplete.
20A. anag. LACIEST.
22A. writer = PEN, couple of guests = GU, at home = IN.
23A. nothing = I, grim = DOUR.
24A. judge = REF, around false statement = LIE.
DOWN
1D. Cryptic(-ish) definition.
2D. horsey = EQUINE, not finished; bull = OX.
3D. hidden reversed in angulAR BEZel.
5D. 6 = VI + 5 = V + anag. LAID.
6D. shake off = LOSE around one's head = O.
7D. last primrose = E, Michaelmas daisy = ASTER.
8D. anag. HASELONIRONEDKINK.
14D. double definition.
15D. after tax = NET, duty = WORK.
16D. double definition.
17D. senior = SR around bit of apple = CORE.
19D. container = CAN, one = A, litre = L.
21D. machine learning = AI, reversal of look = LO, tuber = I.