Last week I bought one of these.
https://www.screwfix.com/p/erbauer-emis216s-216mm-electric-double-bevel-sliding-mitre-saw-220-240v/271fvWhy oh why have I not done this before? I've made numerous items of garden furniture before, and done woodwork around the house, all with hand saws and a Bosch circular saw.
I was tasked with making some garden planters for a friend's new house, and one of which was to house a cherry tree of sentimental value brought from her previous house. I made the mistake of asking if she wanted mitred corners to the boards making up the 600mm square 16" deep planter. Oooooh, yes please! Can you do that?
The magnitude of the task by the use of hand saws and getting accurate, tight joints then dawned on me so I bought the mitre saw I'd always wanted.
Boy, does it make light work of accurate joints. I'd already built a 5m long planter with hand tools but it made short work of the cherry tree planter and another long one to take climbing roses.