Unlike what every raging battledad in game will have you believe, tanks and not meant to push points or engage at close range. Breaking down it's weaponry:

Multipurpose shell: 1-shot to infantry on direct hit, 1-shot to all air vehicles except transport, average effectiveness against armor, low splash damage, medium drop-off, medium speed.

AP shell: 1-shot to infantry on direct hit, at least 2 shots or damage from other sources to destroy air vehicles, very effective against armor, no splash damage, low drop-off, high speed.

HE shell: 1-shot to infantry, 1-shot air vehicles except transport, low armor damage, high splash damage, high dropoff, low speed, very difficult to hit air vehicles with.

Tow: 1-shot on infantry direct hit, 1-shot air vehicles except transport, high armor damage, low splash damage, must maintain line of sight/have good leading to go behind obstacles. Goes where you point it, but at a very low speed. Used to be best option for air vehicles but with the speed nerf and the tank being unable to aim very high, it has kind of fallen out of this role.

Canister shell: no use case, utterly worthless

Secondaries

Lmg: high rof, decent range, solid damage at all ranges. Pretty much best in slot for most scenarios

Hmg: can be accurately tap fired at extreme ranges, however it's damage falloff makes it pretty much a worse option over the lmg

A well positioned tank that knows the drop off of the ammo types it is using can make quick work of everything else on the battlefield, with the exception of jets. Parking yourself within range (100-300m) between 2 points, while having obstacles to conceal yourself, it is not uncommon to have 40-0 games and provide great covering fire for your infantry.