One option that nobody shared with you is the CNAT. The problem is that there is more variability on those than, say, a True Hard Arkansas from Dan's.

So you need to choose if you optimize for cost or simplicity.
The simple option is the synthetic 12k stone or a good condition barber hone. If you want to optimize for cost, the lapping film or CNAT goes in that direction.

In my case, I've been optimizing for cost, and I can honestly say that I don't have enough time, so that is something that drags me down.
Now if you have plenty of time, you may even end up enjoying the process of lapping and burnishing a natural stone.

As for the strop, I heard good things about the Ruitertassen strop on Fendrihan. I have a bench strop from ClassicEdge you can try too.