I dont go to Buda that often. The castle district is beautiful and a tourist haven. But my son and his family came to town, so we did the required homage to Buda. I knew what we would find, but it was worse than I had expected.
The Fisherman’s Bastion area, wonderful. Best views in Budapest. You should walk down the back stairs to the river if you can.
The Castle proper, beautiful, majestic, worth the time.
Mathias Church, one of the most uniquely amazing churches I have ever been in. Recently restored it is stunning.
Some other ideas: https://zsidai.com/buda-castle-budapest.html
BUT!! Everything in between a maze of construction and tourist crowds. Horrible. You see the current government is rebuilding the Castle District to its pre-WWII glory. That means reconstructing massive palaces and riding stables and ….
So, if you are into museums they do exist in the District. They are fascinating and you could spend days in them. If you are a wandering strolling sort of tourist, do go for the points I mentioned above, but figure its 3 hours tops.