I guess I've been in one too many nasty gas station bathrooms... One of the nicest things about owning a van is never having to use a public restroom.
I am not familiar with the Sandinrayli brand portable toilet, but I've owned a Thetford Curve for many years. It is used on an occasional basis in a basement that does not have plumbing. I like that it is intuitively easy to use, compact and lightweight therefore very portable, and easy to clean (can be hosed down). Like a traditional toilet, there is water in the bowl, using it doesn't smell any worse than using a regular toilet. I have good results with Happy Camper tank treatment. Emptying the tank isn't a pleasant task but it isn't messy and it doesn't take long. I simply carry the tank upstairs and dump it into the house toilet. I would be uncomfortable dumping it in a public toilet, even though there is nothing wrong with doing so. That is the primary reason why I don't have one in the van.
I've used a simple (non urine diverting) bucket toilet in the van for the past two years. The bucket is inside an ottoman (wood box with a regular toilet seat mounted within). There are no moving parts to break, there's nothing to clean, and emptying the bucket literally takes seconds. Males can standup to pee, females can poop and pee simultaneously, and it accepts any type of deposit (eg. feminine hygiene products, food waste, vomit). I used to fill the bottom of the bucket with wood pellets, it worked ok, but required storage space for pounds of pellets and resulted in a bulky and heavy kitchen sized trash bag to dispose of the contents. I recently switched to LaSyl* absorbent powder, it turns urine into a lightweight gel, resulting in a package small enough to be contained in a grocery bag.
Vanlife wisdom says separating pee and poop eliminates odor. All I can say is my poop smells. Period. Urine alone can also smell. There have been very few times when odor has escaped from the ottoman. Occasionally, there's a slight odor when I lift the toilet seat lid, reminding me that I've been inattentive. When it's just urine, the amount of time between emptying can range from 3 days to 2 weeks depending on frequency of use and ambient temperature. The amount of time a poop deposit remains in my van is measured in minutes, not hours.
I have no experience using a commercially manufactured "composting" toilet. I've watched dozens of videos and don't understand the appeal. In traveler use scenarios, the poop gets dumped in the trash and the pee is emptied into a toilet or dumped on the ground. It essentially functions as an expensive, complicated bucket toilet that requires electricity. It is a hassle to empty (requiring some amount of disassembly), difficult to clean, and requires anatomical adaptation to use.
Portable toilets on Amazon start at $75, so yours won't yield much money on the used market (even if its unopened). There is no singular best toilet solution. Don't let YT videos fool you, portable toilets are a popular choice in vans. Since you already have it, give it a try and see how it works for you. If you don't like it, you'll have a definite idea of what to try next based on your experience.
* demonstration video of how LaSyl works: https://www.amazon.com/gp/product/B09G2XPDSY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1