Battery Power for Pi4

This gizmo is really nice. It powers the Pi4 with no lightening bolt (symbol for underpower) for a good solid 1.5 hours

BUT. There's a problem. 

I can't plug it in like you would a laptop and still have it be powering the Pi cuz it automatically shuts down once it sees incoming power at the charging port, which means, that if I'm on battery power, and the battery starts getting low, I'll need to shut down the pi (safely), then switch power inputs, then turn the Pi back on again

I briefly considered the PiJuice Hat battery pack, but, it's in the way of the heatsink so it wouldn't actually fit anyway even if I used one of the smaller heat sinks (I'm using the Ice Tower which I really really like)

Huge, yes, but in the way of any Hat I might try to add (unless I use a T-Cobbler, which, I guess, might work, but that's still a kinda small battery, and besides that, the T-Cobbler separates the 2 rows of pins, so I still wouldn't be able to plug it in)

That's not an ideal situation for what I'm trying to do

Now, I have another thought, but I haven't ordered the batteries yet...

My thought is to use a bunch of 18650's and hook them up thru a 5V buck converter, then I could hook up the charger to the batteries and it would still be going thru the buck converter so it'd still only be 5V coming out of the output

I'd like to hear that this is a workable idea, or I could use another solution

Help ?