I was looking for something similar a few months ago because managing bookings over phone calls and WhatsApp was becoming really difficult. I wanted a system where customers could book online and I could manage everything from one place.
After trying a couple of platforms, I ended up using MotoShare, and it's been a good experience so far. It handles vehicle listings, online reservations, availability, pricing, customer details, and booking confirmations in a fairly simple way. I also liked that both the customer and partner sides are easy to use, so there wasn't much of a learning curve.
If you're running a startup or a small rental business, I think it's definitely worth checking out. It may not have every enterprise-level feature, but for everyday rental operations it covers most of the essentials without making things complicated.
My advice would be to sign up and test the complete booking flow yourself before deciding. That's what I did, and it gave me a much better idea of whether it would fit my business than just comparing feature lists.