They should work fine.

How is your setup/level of automation and can you show what you are trying to do?
A bit easier to try to help that way.

A short brief:

The running of the train while it is in service (as in it's colored) is governed by the sensors and automation you have set up.
The running of the train while it is out of service (white) has different tiers of work/automation:

Fully manual - Either let the trains take their intermissions (time between each leg/part of the contract) at the platforms or manually send them out of the way to stabling tracks or sidings. You have to manually put it back into service by the reuse/assign button that appears on the platform. Click that - then the train for putting it back into service.

Partially manual (starts with shunting commands upgrade) - You switch the train to shunting mode, once the previous leg is finished, when you need it out of the way, and add commands to telling it what to do until they start on the next leg and then it is switched out of shunting mode when there are no more commands. This have to be done for each train that you want to shunt. You can add reuse commands that assigns it back into service automatically.

Automatic - You use stabling/shunting sensors to switch the trains over to shunting mode automatically with commands preset as rules, and you can set different rules based on trains next origin/destination as well.

Space saver - You can use CY to save space instead of having shunting tracks.

You should stable the trains at the station that they are due to depart from. If the train during the intermission has to get to another station, you should let it run like a normal train guided by the sensors like the rest of your network. If not you have to shunt it all the way at 30 km/h. When it arrives at the starting station for the next leg, catch it with a stabling sensor (or switch to shunt mode manually) to automate the rest of the intermission process.

Currently im using stabling sensors, paired with sidings, more or less trying to go fully automatic

i think the issue is my lack of grasp with the regionals as they seem to be a very big jump in skill and understand-ability

Maybe... Do you have some screenshots of your setups and shunting rules? To see if there's something obvious, I mean.

Regionals are just contracts with multiple legs, and they need to be waiting somewhere (even on the platform is viable as well) before the next leg is due. Then they need to be "accepted" back to the map by a button on the platform or part of shunting commands (kind of like you start off by accepting trains into the stations).

I think i figured out the issues, it was to due with how i set up my stabling groups.

Entirely on my fault, it just seems to be a bit of learning curve for rn

I suggest starting with a simple setup, like chose a yet-unconnected station for first Reg trains & just stable the trains at the platforms. This should quickly provide enough points for the Shunting Commands upgrade so the Reuse command can be queued. It helps a lot in reaching the throughput quickly as you can enqueue the commands during the intermission while the simulation runs at 25×.

Once Stabling Sensor is reachable, build it there & configure it just for reusing. You have a fully automated red points generator so you can move to some other station & maybe establish a shunting yard there.

This is the way how to make the learning curve less steeper - you first do something manually, then enqueue it to a queue & then configure a sensor to do it for you.

the guides tab here in steam has an excellent guide on setting up regional trains. i would suggest running through that a couple of times on a different map till you get the hang of it so then you can reload the map your working on and apply the stuff from the guide to really get you going.