Don't expect much in the way of tactics at level 3.
Levels 1-2 are the "starter levels" to introduce new people to their classes and the basics of the game. Level 3 is where you actually get to start making some decisions about your character and it increases from there.
There were a lot of complaints about 4E being too much of a "tactical miniatures wargame" then, well, whatever those people thought D&D should have been, so a lot of that was cut out from 5e (powers, measurements in squares, etc..).
The fact that 5E is also rules light also makes it less tactical.
So you're experiencing a conflagration of problems: Early levels have the least tactical elements. 5E was designed to be a much less tactical game, especially in comparison to 4E and 5E simply doesn't have the amount of rules necessary to support highly tactical play.
Solutions include: Don't play low-levels. Use a lot of the optional rules. Make overt attempts to be tactical with your party and ask the DM to play the enemies more tactically too.
I sometimes find that low-level play is the
most tactical, especially first level play, because extremely tactical play happens when the PCs are desperate for any advantage. When you're twelfth level and you meet a small squad of hobgoblins, you don't mess around with caltrops and lighting and stealth--you just kill them and move on. But a first-level PC meeting that hobgoblin squad on his own will be extremely tactical, trying to find the right place to engage them where he is surrounded by difficult terrain and has a retreat corridor open and a clear field of fire and 3/4 cover or better from which to shoot and a chokepoint seeded with caltrops...
If you feel that 5E combats are samey, I advise you to:
1.) Vary the difficulty,
2.) In different ways.
Four potential ways to make combats hard are:
1.) The conflict takes place in unfriendly environment (e.g. Phase spiders fighting in webbing as per DMG 105, or fighting orcs on the edge of a 180' cliff drop).
2.) The conflict is against foes who are personally much stronger than the PCs.
3.) The conflict is against foes who are much more numerous than the PCs.
4.) The PCs have a goal in this conflict which cannot be feasibly satisfied purely by inflicting violence (e.g. get the snatched purse back
without using deadly weapons and going to jail; prevent any of the civilians from being killed by the bandits).
5.) The conflict is against foes who have a wide range of tactical options (due to magic or other special abilities like webbing or nets).
You can also vary encounters by making some of them
not have to devolve into combat, but that's a separate topic.
So anyway, mix and match from the various options for difficulty. That could mean a tribe of kobolds who Help each other try to shove PCs off 180' cliffs in the mountains; or a werebear who is
really a necromancer Magic Jarred into a werebear's body, who shadows the PCs until they are already in the middle of a tough fight and then summons an Air Elemental and attacks the rear; or an entire battalion of 200 centaurs who claim you are trespassing, but will grant you safe passage off their land if one of the PCs can defeat their champion in a fistfight (no weapons allowed). Or a horseshoe contest that doesn't involve combat at all.
One underappreciated aspect of 5E's ruleset, I think, is that large quantities of foes still work really well at high level. If you as a DM know techniques for running a fight with 50 hobgoblins efficiently (i.e. pace stays fast, more time spent on player decisions than die-rolling and arithmetic) you open up a whole new category of epic 5E. You're not limited to dragons and liches, 5E characters are weak enough that a mere handful of Nycaloths or Stygian Skeletons (anyone with good mobility or ranged combat) can provide a stiff challenge for 20th level parties... which means that you don't have to abandon your campaign at 16th level! I can't wait until one of my PCs hits 20th level--I have a whole shipful of 50 Oni mercs from the Trading Company for them to lock horns with, only in 5E there aren't any AD&D-style spells like Mass Charm that can trivialize a platoon of Onis, so even 20th level PCs will have to fight smart and be tactical, or they will die horribly in Oni stomachs. Actually I won't wait for them to hit 20th level before I hit them with this, but at 20th level they might actually engage the foe instead of fleeing...