OK, I do put them in the buggy if I need them to be in there. If I don't need them to be in there, then I would be happy to let them choose whether to go in or not.
I did have to learn to centre my own needs a bit, because if you keep skirting around what you really need (e.g. to get home before you get really hungry/cold/narky) in order to avoid upsetting your toddler then you'll end up damaging your relationship. This definitely happened with me and although I said I have a nice relationship with DS1 now, there was a period in the middle where it was really rocky and I have huge guilt/regret about this.
I do think that if you don't get your head around the confident leader role by the time they are about 3/4, and keep relying on tactics like just waiting for him to lose interest in something before you leave a shop, you set yourself up for a scenario that I absolutely did and I think is not completely unheard of in gentle parenting circles, because this kind of skirting around, not actually enforcing boundaries, waiting for distraction to do it for you stops working as soon as their attention span and understanding increases just enough that they know what you're doing, because at that point they start to push it on purpose. I think it's partially out of curiosity, but it's also about feeling secure, like that testing the rollercoaster safety analogy. I found Janet Lansbury very helpful with this, she has a nice balance IMO between being gentle and respectful towards the child, but not being a slave to their every whim and being a pushover. There are a lot of gentle parenting resources which just go "blah blah obviously you must also have boundaries!" but don't really explain what that actually looks like, whereas she does IME.
Two more analogies which helped me with boundaries are thinking about a job where you have a boss who is really wishy washy and just says "Oh don't worry, do whatever you want to do!" Sounds great, but also, confusing? When I'm in a position where I know that there are things I'm supposed to be doing, it's helpful to have some direction from someone more experienced. A boss who has inspiring ideas and gives clear instructions but ALSO is empathetic and listens to me would basically be the perfect boss - and I think about that in parenting.
The last one for me is about framing my role as being responsible for them (which, obviously, but it helps me when I know that I need to push something and I really don't want to/am dreading the conflict). So for example I say something like "It's my job to keep you healthy, and brushing your teeth is something that keeps you healthy, so I have to make sure that your teeth get cleaned." (Either to myself, or directly to the child).
Gentle parenting is great but don't get too caught up in social media parenting. The How To Talk books are great and practical. If you're averse to conflict in general, this might be something to explore, preferably before your child turns 3, or you're likely to struggle with the next stage. Toddlers (1-3 ish) are brilliant and funny and cute and unpredictable, but 3-7 (especially 4/5) can be a bit of a battle of wills, even (especially?) if you're trying your hardest never to engage in the battle.
Lastly I think there is a huge amount of value in simply setting up their expectations - so for example, I never used to get DS1 dressed unless we were literally going out right this second. I thought that it was a waste of a battle because he didn't want to and I didn't need him to so why would I bother. DS2 came along and DH got him dressed every single day and I thought he was mad - but actually, him having developed that expectation made such a huge difference. There is this theory in gentle parenting that if you let them do what they want the majority of the time and just make them do things occasionally when you absolutely have to, then they will be willing and cooperative because they understand that it's really important this time. This is just completely false IME, if you have some kind of "norm" in your head (like getting dressed) and you think you're letting them off that norm all the time to be fun, they don't experience it the same way you do. They think that it's normal not to get dressed and when you try to insist on it they fight it because it's a weird, abnormal, uncomfortable thing to do. You have to establish the boring normal in order for letting them off the normal thing to BE an exception and therefore be fun.