If you have no side effects, mainly no nausea, and you are hungry, then increasing the dose is fairly low risk. Usually you will get some indication of adverse effects below the dose where they really kick in, like mild nausea at 3mg would suggest that going to 4mg it is going to be worse. The problem with increasing doses at any stage or to any degree is of worse side effects, and if you are unlucky then they can hit pretty hard, and you end up nauseous or worse puking for a week. The odds of this happening are never going to be zero, no matter how careful you are and how slowly you increase doses, but it is much more likely if you increase doses quickly. In the studies the worst gastrointestinal side effects were typically at the 2 - 4 month stage where doses were increasing, so for tirz around 5-10mg and reta 4-8mg, and then very slowly improved. It does not sound like you need to increase doses based on weight loss, but hunger control is a major part of making weight loss sustainable and wanting to or eating chocolate and drinking beer does not sound like reasonable hunger control
The simplest way to reduce this risk while increasing doses is to dose smaller more often, as side effects are nearly always worst at peak levels, 24 to 48 hours after a dose. But you need to look at GLP plotter and play with it a bit to see what happens with different doses and timings. So at your current dose of 2mg , you could add 1mg half way between doses and see what happens.
It is important to know that the half life of a week means that drug levels will continue to rise for up to 4 weeks after a dose increase, so that peak side effects might be after the 4th dose at a new level - look at glp plotter
If you cannot be bothered with twice a week dosing the risks of increasing to 2.5 with zero side effects at 2mg are very small. And increasing to 3mg is pretty unlikely to cause problems either. But still check out GLP plotter , it makes the doses and timing and side effects make more sense, as the weird pharmacokinetics of GLP's are the opposite of intuitive, and totally different to just about every other drug in existence.