I don't think they are horrible; after all it's where surf culture was popularized. But it's hardly tropical, and places like Venice can be scruffy. The beach near the Santa Monica pier looked OK. Santa Monica is about 15 miles from the stretch of Hollywood Blvd that would be of interest to you. Which can take well over an hour by public transport.
If you do go, the new Academy of Motion Picture Arts & Sciences museum is very cool (not sure that is the proper name). The Hollywood Roosevelt hotel is worth a look even if you don't stay there; it is very 1920s, the stars of the golden age used to stay there and the first Academy Awards was held there. It has an iconic pool area with a bar where you can get a drink.
You can't really wing it on the studio tours; they should be booked in advance. I've never been to the theme parks/amusement parks there. The cemetery tours are very interesting.
This woman has been a speaker at the film festival and is very interesting, in case she happens to have any events going on whilst you are there: http://www.glamamor.com/
This is the walking tour lady: https://oldhollywoodtour.com/
About five years ago we hired a woman for a private tour; she picked us up at the hotel and drove us to all the landmarks, more than 120 miles over the course of a 9-hour day, such as a lookout area on Mulholland Drive, the downtown city hall/courts complex (where the OJ Simpson trial was), Santa Monica pier, a look at the Chateau Marmont hotel, a cemetery in Westwood (?) where Marilyn Monroe and many other stars/actors are buried, Angel's Flight, Chinatown, and other places we requested.
It was VERY expensive - about 700 dollars and I gave her 100 tip -- but we felt worth it as it covered much ground and ticked a lot of boxes. She would pull up, let us out to look around, and return in 20 min or whatever made sense, so we didn't have to endure parking, and could be dropped off right up close to the things we wanted to see. Saved a ton of time. I can look up her info if you like. She was a pleasant 40-something woman and her vehicle was a very nice, clean SUV.
The farmer's market is sort of a tourist trap but amusing enough to wander through; there was a stall selling mind-blowing roast beef sandwiches and there is a sort of restaurant there, Dupar's, that is famous and in lots of shows and movies. Near there is a large open-air shopping centre with high-end stores.
We have not gone to the LaBrea tar pits but some people enjoy it. There also is a stupendous art museum called The Broad (rhymes with go, not aww) if you like contemporary.
A day trip to Catalina Island is on my bucket list; it's historic and ritzy. https://www.lovecatalina.com/island-info/plan-your-visit/catalina-island-visitor-center/
Good luck!