Haven't been to Mexico much a group is planning a trip end of spring to the Riveria Maya. They want calm beaches, all-inclusive, young adult friendly and 3 or 4 star. What are your recommendations? Any hidden gems?

Covering a large area along the Yucatán Carib with many different options...Playa Mujeres to the north of Cancun; The Cancun “hotel zone” where grand hotels line the beach, the most touristy area for those who just want to stay on the property; Playa Del Carmen with its many resorts and boutique AI hotels and nightlife off the resort, Akumal for snorkeling with turtles and a quieter vibe, Tulum beach hotels...and the hundreds of oceanfront resorts in between...

How long a stay?
Will you stay on the resort? Or are any more adventurous and want to explore the natural beauty and history?
Is golf important?

I would look at a map and do a little research on the different areas and see if any area matches what you are looking for. There are several resorts that attract young adults, and if you want to enjoy bars or nightclubs off-resort then Cancun or PDC would be worth a look. If Cancun, the calmest water is at the top of the 7, we like the RIU Cancun for example.
3 or 4 star here is hard to advise on, do you have a budget for your accommodations to get more useful feedback?

Crmoores has a good overview. But as you specifically said Riveria Maya, you are on the spot for calm beaches, young adult friendly, all inclusive properties. Likely in the area south of Puerto Morales to north of Playa del Carmen. You will find 3, 4, 5 stars to match. Various travel websites will sort based on stars and price. Travel agents and tour operators will help as well.

I do suggest that all inclusive may work for a group. No issues of transportation once onsite. Multiple restaurants, bars, and fun!

I'll look at the Map definitely do not want to be near Cancun hotel zone. We want calm white beaches and a fun not rowdy place. Haven't really looked at a budget usually like a place where food is excellent and have top shelf alcohol.

TYIA

Excellent food and top shelf drinks can be had at many resorts for a price, along with calm water (with a sandy entry) and a fun but not rowdy vibe. The hotel zone is actually a good fit, just need to find your best-fit resort.

Maroma Beach also comes to mind for the calm, gorgeous beach, not sure if the fun is there...Google the resorts there...

The Hilton in Playa (I know, it was the Royal before) is in a great spot right in Playa. We haven’t stayed there at all, but it has been a favorite spot for friends visiting the area who wanted an AI right in town on a beautiful beach where they could walk to other bars and enjoy bands. But check recent reviews since Hilton took it over...

Do you want an adult only resort? They can be a bit boring for us alone, but with friends it is a great choice for the best food/drinks and a younger vibe...

[spoiler][/spoiler]We’re enjoying a long weekend at the RIU Palace Mexico, one of two RIU Palaces located in the beautiful gated community of Playacar. Right now we are enjoying gorgeous weather, excellent cuisine and drinks, superb service with pretty good entertainment, and the beach and Caribbean water are gorgeous as well.
It’s a younger vibe here with many small groups of couples from all over. The only reason I didn’t suggest one of these Palace resorts (or one of the other sister RIU properties) is the water can be a bit rough at times if the conditions are right. This week the water is quite calm...
Meant to add that staying at a resort in Playacar you are also a short taxi or longer beach walk into Playa if you want to enjoy any of the many fun bars there!

Also reverting to Orange on January 25