Sorry, but there's not many people on these bits of the boards with a lot of DLP experience, so it can take a while to get a reply - it's not like the threads for the US parks where there's thousands of people wanting to share their opinions. If people aren't online then it'll just take a bit longer than you expect.
Now I'm not a big table service in the park sort of person - takes too much time (food service in France is a lot more leisurely than elsewhere) that I could be using to ride rides, see shows or visit shops in my opinion! Despite that I have eaten in both Walts and Silver Spur Steakhouse - the meals I got in both were good, but I hesitate to say that either was a "must do" in that they didn't stand out as things I would have regretted missing out on had I not done them if you see what I mean. I think if you're certain you want one TS meal in the park, then Walts is probably the one to do but check the menu first.
Outside of the parks however I do try to go for at least one TS meal per trip, either in one of the hotels, or in Disney Village. The Steakhouse in the Village used to be good but has (IMHO) gone downhill recently in terms of food quality, but the atmosphere still might make for a memorable meal. I also like the Manhattan restaurant in the Marvel hotel, which is mainly Italian cuisine and feels quite fancy. At the Newport Bay hotel I'm not sold on the Yacht Club, but then I'm not a huge seafood fan, so whenever I'm there we end up at the Cape Cod buffet.
However still none of these are exactly screaming out at me as being must do's either. Perhaps that's because the two best restaurants on property were always in the
Disneyland Hotel which is still being refurbished. Innoventions (yes it was a buffet, but it was at a whole other level, plus sometimes had characters as well) and California Grill (apart from the name and one or two shared dishes, didn't have a lot in common with the one at WDW but was excellent in it's own right) I would say both met that sort of "stand-out" category that you were probably after. Unfortunately they are not going to re-open until 2024, so you're out of luck there.