Harsher discipline for a toddler? That sounds like odd advice, runner. I would ignore it, tbh. Be a nice, fun, kind parent; you also need to have firm rules and boundaries, but that doesn't mean you have to be 'harsh' or use punishment.
The old fashioned school of parenting was authoritarian - punishment/reward, 'because I say so' etc. This can sometimes lead to resentment and tbh doesn't really work very well long term.
Some people react against authoritarianism but fail to put boundaries in place - which can lead to permissive parenting - 'let them do whatever they want'. This can be confusing or even frightening to a child and can lead to them 'acting out' to try and find rules and boundaries.
The best way to parent is with clear, firm, and loving boundaries. Children need structure, instructions, engagement, coaching, help to learn.
It's the difference between being aggressive, passive, and assertive.
In reality most families probably end up with a bit of a mish-mash of those parenting styles, and most of us make mistakes all the time a lot of the time. I think if you keep trying and keep reminding yourself that it's hard work, you're all doing your best, that you all love each other, mostly hopefully it comes out okay.