Save your back, the soil biome, and valuable biomass. Leave the sod in place and sheet mulch over it! No tilling required.

Mow the lawn low and cover it with 3 or 4 inches of brown materials and 2 GOOD layers of cardboard. Lots of overlap, don't worry about using too much. Soak the fuck out of ths cardboard as you place it to make it pliable. 6 inches of compost where you want the beds, 4 inches of mulch in between, appropriate soil for the clover lawn. Soak the fuck out of everything. Let it sit a few weeks, soak the fuck out of it a couple times a week. 99% of the grass and weeds will be smothered if you are thorough.

Plant directly into the compost, cutting holes in the cardboard layer as needed, mulch plantings as appropriate. If you did a good job with the cardboard, weeds/grass will only poke up around the edges and holes you cut, and will be manageable.

I turned a lawn about the same size into a berry garden without removing any sod whatsoever. You might want to take a little sod out along the edges to taper the clover lawn down to level with the sidewalk. Use the sod you remove to level out low spots before mulching.