No, Ring Fit Adventure and Astral Chain aren't in the least bit suspicious because promotional Spirits have never been consistent for different titles. Super Mario Party Spirits came out after the game had launched in January 2019, NSMBU Deluxe Spirits came out in late May 2019 which was 5 months after the game launched, Link's Awakening Spirits came out 3 months before the game itself even came out, Octopath Traveler got Spirits on the second anniversary of the game's release even with a first year anniversary a possibility, Cuphead Spirits launched a few weeks after the costume was included with Byleth's wave of DLC and months after Cuphead had launced on Switch... Etc. Resident Evil, Daemon X Machina, Pokemon Sword/Shield, and Trials of Mana were all Spirits that launched with their respective games, so Pokemon isn't even uniquely qualified in that regard either.
You can talk about how precedent and how "I don't think Sakurai..." aren't the most compelling arguments, but the least compelling argument of all is the "Sakurai/Nintendo intentionally put stuff in to throw us off the trail." I've heard this same idea mentioned time after time as justification, and never once has it panned out because they've never really cared that much about throwing us off the trail with misdirects. It's never once been a priority for Nintendo, and Pokemon in the pass would have been selected well before Byleth was even announced, so they also couldn't be reacting to people figuring it out specifically either. Sakurai is pretty straightforward guy at the end of the day and his actions and speech should generally be taken at face value instead of trying to figure out the supposed "4D chess strategy" he's using to try and keep us from discovering the truth. In every instance of a related situation, stuff being miss or seeming suspiciously like other things are specifically coming, it's just been reality.
Precedent is not the end all, be all, and it can be broken, but that's just kind of unhelpful as a point of conversation and especially for speculation because its such a non-starter in the same way that anything can happen is a non starter. It's fine if you're just trying to support a very specific character and be hopeful about them, but that's character support and not so much speculation. Exceptions to rule do not inherently break rules as a general concept that tends to be correct either. Hell, rules of grammar and math often have many exceptions that have to be learned, but generally hold true and are thus still considered rules. Breaking the "limits" of Smash so to speak makes for a nice narrative, but it's still just as steeped in rough criteria as it has generally always been and some of those limits being broken were either due to the natural progression of the game into something more grand or broken with very specific exceptions in mind. Again, I'm not saying precedent and rules are the end all, be all, but they are also just general guidelines that serve to create interesting conversation topics and at a least provide some basis in speculation.
