I won’t say I love Plank. But it’s really convenient, basically you can do it at home with little space. You only need to download Interval Timer apps.
You can go YouTube to search the correct pose, and find some challenges at Pinterest. The reason to train the abs is to protect our lower back and get strength. If you are going to lose weight, start with burning belly fat.
Other choices like wall sit, boat pose, bird dog crunches also good for abs training.
No time, don’t want to commit gym membership <— excuses, do the things that make you happy and healthy.