insist on you putting something under "comments", Cash App being one in particular.

If they must enter something I prefer for modeling, consulting, or photography.

I would think its often inexperience. Sending money by apps is still relativley new to this lifestyle. It was almost unheard of just a few years ago as it was close to a 100% cash business then, so there is still a learning curve for a large segment of the client population. As an example, for as long as I have been doing this, I have still yet to pay a provider by an app.  
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Then add in many men are new to p4p in general and dont know the etiquette as yet. Its still a work in progress for many I am sure. Any new wrinkles to a business will produce some hiccups for a time and I think that is what you may be dealing with.  
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The other issue is that since the Newbie Board here essentially went poof, its void created one less space for men and women to get sound advice on a whole list of potential issues that can pop up. It was a great place to learn the ropes and get info on basic etiquette and learn unwritten rules.  
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Clients are dealing with similar things as Covid brought in many women who have not adopted the professional norms of SWs that preceded them. Many of those women would have received proper guidance and advice by both caring men and women on that board but it doesnt carry the same prestige since TER shut down during Sesta/Fosta and basically the same thing occured during Covid.

My fave example being the unprovoked random 3am text with hearts and butterflies.

I don't think it's that, I think it's just plain stupidity which seems rampant in the world today. In the line of work I retired from I dealt with the public quite a bit and soon after I started came to feel like mankind has no future because of the legions of idiots in the world.  

Following on Queen Bia's comment,  make it coordinate with your RL /fake RL business.  

I have a regular who I usually sent a deposit with a gift card.   But, when I'm 'out of town' I have a long drive to get a gift card, and once I just couldn't make that drive.  I sent it via electronic payment, and she specifically said enter 'massage'.  If providers aren't saying EXACTLY what to enter, then it's sort of on them, IMO,

If you dont like how someone may do something, give them instructions on how you want it done. Since p4p issues can be so different than RW ones, with so much more added risk, all the more reason do so.

I’ve had multiple ladies clearly instruct me on what they wanted me to put as the note when giving me their username.  

I tell them to put coffee or pizza for smaller amounts (deposits), and “tickets” for larger amounts. There should never be larger amounts, ideally, but every now and then someone shows up without cash.

√ "Consultation"  
√ "Educational  Seminar"  
√ "Attorney Retainer"  ( For 0vernights )
√ "Housecleaning"  

I have heard that some apps use the "memo" to distinguish what might be taxable compensation (and possibly reportable to the IRS) from gifts, repayments, etc.  Better to avoid "consultation" and like designations.  How about "Pizza"  "Meal"  "Happy Birthday!"

I am a car guy and i buy/sell parts all the time.  

What you put down is unlikely to do anything to help you out. For those that are trying to misdirect, you run into a potential problem of being seen as intentionally trying to misrepresent the financial transaction. While I suspect the chances are small, that could open either of both parties up to charges about money laundering and financial fraud (lying to your financial institution). So when people are saying put something in that is clearly no related to what the provider might be trying to show the world what her apparent services are (companionship, massage, modeling, friendship...anything but sex services) and then they are getting payments indicating other shit, well talk about red flags.