You basically do not create

You basically do not create separate blocks without insulated rail joiners. They hold the rails together in alignment while also keeping them from connecting electrically.

I'm sure it's possible to make insulated rail joiners, but it will take either expensive tools or a considerable amount of time and effort. For example, it's straightforward to 3D print some insulated rail joiners - but you need a 3D printer to do that. Even if you have a printer, you'll need to measure the rails carefully to get the right dimensions. I would use a dial caliper to do that, and even a cheap plastic one of those will cost close to 5x as much as some insulated rail joiners.

I don't know where you are in the world, but in the US a package of insulated rail joiners runs between $2 and $4. Virtually every store that carries track carries them.

One way to avoid insulated rail joiners ... is to switch to DCC. But that will involve many of its own issues. And it's certainly not cheaper.

Atlas Controller and Selector

The Atlas Selector allows the connection of one of two cabs or throttles to each of four blocks.  It switches only one rail, the other wire being unswitched, and may be ungapped.  Just be sure to connect that common rail to the throttle.  As you mention temporary setups, I second the suggestion about using insulated rail joiners.  My Great Falls and Pinkland is an oval with two spurs and a two-track yard with lead.  The oval main is divided into four blocks, so I effectively have 7 blocks, all using insulated joiners in the one gapped rail.

The Controller switches both rails for the reversing loop or wye.  Failure to do so brings things rapidly to a halt with a short circuit.

In the Atlas booklet, "Wiring Your Layout", Paul Mallery discusses the application of the various Atlas components.  He even includes a wye with one leg being a multi-track stub yard.  He shows the track, the locations of the various insulated joiners, and the wiring.  The diagram includes a Controller and three Selectors.  I have no financial interest in the booklet, but I recommend it.

Having looked

Having looked in the two hobby shops I frequent, I have had no luck finding HO scale insulated joiners

the one shop has a limited selection of HO because the owner sees no value in it, and the other one isn’t always easy to stop in

i do have plans to eventually invest in them as life would be much easier, but for now I’m stuck doing even more complicated things.  Getting the selector to match the controller took almost a month alone with how little time I have to stop at the one shop that has more HO stuff.

but, I am hoping to get those joiner types one day

Joiners aren't scale specific

Joiners aren't scale specific in most cases, and can be used with many sizes and scales of rail. Insulated joiners are generally fairly soft plastic, and can be used with nearly anything from code 55 to code 100. It's the base of the rail, after all, that determines the fit. Atlas makes 2 styles of insulated rail joiners, a bright orange and a "clear" plastic. Either one should fit your rails.... I prefer the less visible version, myself.

You don't need insulating rail joiners.

You just need to cut a gap in the rail, and fil it with styrene and acc.  Oncce the acc sets up, a small file can be used to contour the styrene to match the rail profile.  The plastic bread clips used to close the plastic bags bread comes in work perfect.  The purpose of the styrene as a gap filler is to keep the rail that has been gap from moving back together and closing the gap.  You can probably get 6 or more gap fillers from one bread clip.

Alright

Ok, that should make my hunt for insulated joiners much easier then since they need not be scale specific

Temporary setups

The only issue I have with cutting the rails is, one, I only have a wire cutter, which works well to cut track into a couple parts, and two, that makes temporary setups forced to always run a block system, which I don’t always need to do.  The joiners also seem like the more flexible option in some cases

wire cutters

The wire cutters will certainly separate the track into two pieces, but the ends will almost certainly be mangled and need to be filed. If you don't clean it up, you'll have constant derailments. I'll guess that you also don't have access to good tools, which will make even this job quite an effort. If you're using many types of pre-fab track, especially sectional track, you could use a razor saw and carefully cut a gap in the rail, then fill it with a piece of styrene. But that too will need careful trimming to avoid causing derailments. A box cutter isn't going to do that- I would use an Xacto knife or similar.

Just order some rail joiners from one of the major online houses. If you're in the US, try this: https://www.modeltrainstuff.com/atlas-ho-55-code-100-insulating-rail-joiners-24/ They're $2 for a package of 24.

Wire cutters

I’ve only ever used the wire cutters once for a rail project, being my Gauntlet track and cutting the turnouts in half.  I didn’t need to do any filing as the ends stayed pretty decent.  The transition between the cut turnout and the rails is a lot smoother than I thought it would be as well 

mad for ordering online, I would if every purchase I made outside of hard cash wasn’t tracked by my parents