baby steps has been really important for us. Spending time really diagnosing exactly where your child is at the moment. Do they know when they are going to pee/poo? Are they able and ready to communicate that to you? Without you nagging?
It may be that (using pull-ups) the first thing is to celebrate wildly whenever your child manages to tell you they are about to go.
And then offer them a potty/loo with no stress if they'd rather go in the nappy. potty chairs can be a good stepping stone.
And then drop the poo out of the nappy into the loo, so the idea of flushing gets introduced.
Baby baby baby steps. If there's any resistance, back off and find a smaller step to offer in a week. Separate out the whole thing into tiny tiny moves. Doing the whole shift at once can be really traumatic for children. A small shift might even be at the level of walking a few steps towards the bathroom before going in the nappy, yk? It just depends what your child is ready and comfortable with. I really believe that potty training can be done without trauma for the most resistant child, it can just take a long time. If you mentally budget for a couple of years to the end of the process, you'll probably be pleasantly surprised. You will also find pausing points on the way that everyone is comfortable with for a few weeks or months.
THere are an awful lot of different aspects for your child to get control of. Knowing when they are about to go. telling someone. Going to the bathroom. Sitting on the loo while peeing. Having the nappy off while peeing. Flushing. Wiping themselves. Sitting down to poo. Having the nappy off to