The F lounge food (not TPR) with its open kitchen concept
prima facie appears to be better than pre-covid. However, dig a little deeper, and whilst the food is tasty and delicious and far from inedible, it is basically just hawker food. SQ have doubled down on hawker food both in lounges and on board, which is fine - they are proud of their heritage and catering to the local market in some respects, but my problem is that I can just get that near home any time for $5 or so. Or if airside get similar food for $7-8 at the Singapore Food Street in T3. When it's the main thing on offer it doesn't smack of premium.
Pre-covid there used to be a rotation of (non-burger) western food in the mix, they often served up a tasty lamb shank. Now it's just the wagyu sliders rotating with iberico pork sliders (and yes at a nearby hawker stall I get delicious burger with far superior chips for $10) or a fancy toastie at breakfast time. They never rotate and seem to lack any form of imagination when it comes to the menu. It wouldn't take a lot, with the live cooking station, for example to serve up an eggs benedict for breakfast - they do the classic Singaporean breakfast of runny eggs and Kaya toast.
Now the beverages in the F lounge are fine though, so can't complain too much.
Oh and as for the J lounge food, it's all relative. It's still better than the slop that QF serve up in their home J international J lounges. Also I recently flew on TK down to MEL, and skipped on the TK contract lounge (Dnata) in T1 and went straight to the SQ J lounge in T3, this was for breakfast. I did get back to T1 a little before boarding so popped into the Dnata lounge. If you rated SQ J lounge food 5/10, the Dnata lounge might scrape by with a score of 0.5/10. Food there was just awful.