lost 2 medium tank regiments and lost all the infantry in an artillery regiment plus all the infantry in a bunkerbuster regiment

Okay so 2 heavy tank regiments at the same time, move them forward and fortify, shoot the tower and then tell everyone else to shoot as well, one of the tanks will get hurt but you can repair

pull back cause the enemy now knows where you are and will go there,

if they are already around the turbolaser which was my problem in this battle:

then individually give orders(This is fking tedious) to your infantry with rockets to focus on enemy vehicles that are anti infantry, have the mortars attacking infantry, transports as well, forget about the med tanks they may have or light because the biggest issue is the towers and have your heavy tanks or heavy and med or w.e you have focus on that tower first and use fortify, then focus on the anti-infantry vehicles then the normal tanks with your own tanks, or mix it around, maybe there's too much enemy infantry so switch ammo to rockets and do splash damage while targetting the vehicles.

The easiest way is simply to accept losses. There is a near limitless supply of those filthy xenos, sorry those valued members of the Alliance (stellaris and Imperial gameplay has had a lasting impact), I simply build a large armoured corp, save the game, and then throw the corp into battle via autoresolve. If it fails simply reload, build more, and then throw that lot in. Keep repeating the process until the desired result is achieved.

If you're tech level 2 and above, send fighters! Turbolasers can't target aircraft and the aircraft themselves move fast enough to evade the majority of the laser fire from the surrounding troops. Artillery is the next best option but you have to get closer to the action. Make sure you have good support for the artillery if you move into attack range or else your opponent will close in and take your forces for a fatal ride lol.

Yeah when I got starfighter regiments, holy ♥♥♥♥ man, they virtually became my go to 1st regiment in every battle and the cookie cutter regiment to defend every system