I'm reposting a guide originally from twitter. I can't link it, as that service now requires accounts to view anything and I'm not interested in that.
Some opinions of mine on what's worth watching/skipping:
1. SKIP! The movie is so awful it turned me off from Star Wars animation for over a decade. Anakin has a padawan now. That's all you need to know.
2. Well worth watching and has some payoff down the line.
3. Nothing important, skip it.
4. Very important for the future but largely unremarkable episodes.
5. There's some recurring characters introduced but the episodes can be hair-pulling affairs. The Deserter, as you mentioned, is mandatory and not half bad.
6. Nothing to see here, skip.
7. Skip it.
8. Big villain introduction, watch it.
9. A must-watch for Kaiju fans and does have a payoff down the line. But ultimately not that important.
10. Has important character development, watch it.
11. Introduces a characer that will return, and also features a Taken homage starring Blue George Lucas. 99% skippable.
12. Really good ones. Features a musical motif that pays homage to a Morricone classic.
13. Some important Mando-centric stuff starts here, but anything to do with Ziro is frustrating for me. Has a bizarre nod in the Obi-Wan show and not what you might expect. Worth watching, but you need time and patience.
14. Absolute artful masterpiece. This was the moment where I went from merely tolerating the show to finally loving it. Required viewing.
15. Important down the line and solid if unexceptional episodes.
16. Some fun Jedi lore in here, and has some followups in the future.
17. High concentrations of Gungans can be hazardous to health and sanity. Unless you're a big fan of Master Fisto and Ackbar, skip it.
18. One of the absolute best. Dark, with some serious character work being done and some ruminations about war itself. Strong recommendation.
19. Mild importance, but if the Jedi's apathy to slavery in the prequels bugs you as much as it does me, this is basically the apology.
20. High quality, some good plot advancement.
21. Mandatory lore and plot progression, and some really great writing and voice acting that elevates a character I once regarded as "nothing" to "compelling"!
22. Mandatory character introduction and the start of an arc that spans multiple series and films!
23. The title alone should speak volumes. It's important, it's great, watch it.
24. The absolute best Clone Wars episodes, and the most essential for Ahsoka's development. If they had truly ended the series here, I would have considered it a perfect finale.
25. As important as it is compelling, another mandatory batch.
26. An unbearably boring subplot about how the banks work, with lots of Senate politicking about economic regulation thrown in. It features the absolute low point of Padme's characterization - and coming from me, that's saying a lot. Skip it! All of it!
27. An arc so artful, so masterful that it made me stop being bothered by midichlorians. Top notch, don't miss it!
"27.5" - you really don't need this, it's all summarized if you pay attention to dialogue later. Still a quality fan effort.
29 - watch this before 28, the author of this list got the order wrong. I know a lot of people hate this one, but it sets up the finale nicely. I say give it a chance
28. It's the backdoor pilot for Bad Batch. Watch it.
30. Grand finale, exceptionally well done, one of the best.
"Non Essential Filler" - Some of it actually wound up not being filler. There's a three parter in there about droids that has some consequences, but it's pretty awful and the important part is summarized. I wouldn't bother with any of these unless you absolutely want to check every box down the line.