i want to make a PvZ speedrun and i would like to listen some help for training because i don't have a mouse for practical use.

I don’t really think it’s feasible to try to speedrun the PC version without a mouse. Can you buy one?

I suppose another option would be to emulate the console version and use a controller.

basic mice are like 50 cents, so they're fairly accessible you don't need a good mouse to play PvZ

If you dont have a mouse, i'd recommend going for strats that rely more on firepower, such as torchwood 3-9 or magnet gloom 5-9. In general i'd say to put your firepower further to the left so that you are safe in case of taking too much time to react to any threat.

Since this speedrun depends a lot on desicion making, you can surely get good times without a mouse, however it will be much harder

I feel like you can train your hands enough to get a decent muscle memory for certain actions, if you really can't get a mouse. Practice repetition. just keep on running, eventually you'll develop a habit to make it easier for yourself.