Lots of very informed opinions here, and excellent advice.

Downshifting before you have to climb is very important, as is progressively downshifting during the climb while maintaining a high cadence, before bogging down under high resistance. Clipless allows you to maintain a secure "grip" while reducing resistance, especially doing 2-3 cog changes at a time.

Practicing standing up to pedal uphill is useful, so that if you do bog down, you have a lot more power to keep moving at a very low cadence (e.g. 20 rpm). Last year this happened to me when I went down to 1st, and barely made the crest. It was scary, I was down to 1 mph, but I refused to go down, I just strained my quads to their limit, and just got to the top. I was dumbfounded. Then I noticed I was on the big chainring. Oops.

For commuting, if you are riding the same route, you can practice the shift changes (maybe using platforms for your testing), and develop routines of when to shift (although these can be greatly complicated by varying situations with car traffic, it still helps). Go for more cadence speed and lower resistance than you need here.

I got some DH SPDs, high quality binding with a platform shell. These provide adequate traction for start ups across intersections without having to be clipped in. I used a dremel on the cleats initially to make release easier, and also facilitate easy bi-directional ankle-turning release. (Turning in is easier for me, knee problem.). I have the spring tension set at it's lightest setting. Only one unwanted clip-out three years ago when I was acclimating. Clipping out when I want out is very easy whether the pedal is up, down, or in between.

For most of the winter, I use platforms, because I need warm boots, and am not willing to go the $250+ route for SPD cycling boots.