Montserrat tour

Look at this
https://www.barcelona-tourist-guide.com/en/tour/montserrat-spain.html

We did not do a tour.
We took 3 trains (metro, flat, cog) and then just walked around.
https://www.barcelona-tourist-guide.com/en/tour/barcelona-montserrat.html

The views are great. We sat on a patio and had beer and potato chips.

We did the tour with Viator Tours. We did the Montserrat tour with a wine Tasting last year . 117.00 now. Great tour with nice buses, well organized. Nice afternoon and didn't have to worry about train times. We've used them several times for cooking classes in Florence and Barcelona. Check out the Sailing Cruise in Barcelona. We've never had a bad experience with them.

Well worth the experience!

There are a variety of “best” ways - and I am just passing along what we did for our own different reasons. After looking at tours (I don’t usually do them), we opted for this.
https://www.civitatis.com/en/barcelona/montserrat-horse-riding-tour/
We wanted to experience the horseback riding - what was probably a highlight of our week because of the ranch, the personnel, our interest, and the setting. They offer variations without.

Plus Civitus, Viator, and Get Your Guide are all resellers. However I couldn’t find this tour (or other options that didn’t include the horse portion) without using one of the above. I usually note the actual company running the tour, but failed to this time. The downside is that I felt there was not quite enough time at Montserrat for me.

Doing it on your own appears to be a great way to experience the monastery (and what I would do with a repeat visit). What is best for you depends on your priorities and needs.