Goal Weight x 12 (Jordan Syatt) has anyone had success with?

The "Goal weight x 12" or similar formulas are much less precise, and have a less-solid basis in research, compared with MFP or TDEE calculators.

Yes, you have to guess at activity level. It works differently in MFP vs. TDEE calculators.

In MFP, your activity level should be what you do excluding intentional exercise, i.e. things like job and home chores. (The step counts upthread are reasonable, maybe even conservative, in that regard.) When you do exercise, log those calories and eat at least a fair percentage of those, too. (Pick some standard percentage to eat back, don't vary it wildly. I'll explain why later.)

Or, link a good fitness tracker to MFP, wear it as close as possible to 24x7, enable negative adjustments in MFP, and eat the number of calories that it and MFP negotiate for you.

If you don't want to log exercise separately, or want the same calorie goal every day, use an outside TDEE calculator to get a calorie goal that considers both daily life activity and intentional exercise. Take 500 calories daily off the total for each pound per week loss you want (be moderate!). Set your calorie goal manually in MFP, and eat that amount daily.

This is one of the better TDEE calculators, IMO, for the reason you mention: It has more activity levels, with better descriptions, than almost any other:

https://www.sailrabbit.com/bmr/

It also lets you compare several different research-based formulas. (They'll be fairly close. You can take an average of them, or pick your favorite.) Because it's multi-formula with more options, the user interface looks a little overwhelming at first. Take a deep breath, work your way through it. You'll quickly figure it out.

Keep up one or the other of the above routines for 4-6 weeks, ideally sticking within 50 calories or so (+/-) of your goal. You can average over a week for a little flexibility, if you like.

After 4-6 weeks, look at your weight trend over that time. If the first week or two on a new routine look wildly different from what happens later, ignore that first week or two and stick with it for another week or two so you have 4-6 weeks of pretty solid personal experience data. (Women of relevant age would want to compare body weight at the same relative point in at least two different menstrual cycles.)

Then, calculate your actual average weight loss per week over the whole 4-6 weeks. Compare that to your intended weight loss. If it's materially different, adjust your calorie goal based on that same idea, that 500 calories per day is roughly a pound a week. (Do arithmetic to figure fractional pounds if necessary.)

That's a more accurate personal estimate than any calculator or formula will give you, as long as you log faithfully, pretty much stick to the same routine **, and handle exercise consistently (that's why I mentioned "pick a standard percentage" earlier).

** If you don't eat the goal calories or close on average for the 4-6 weeks, you can add up the total number of food calories you logged - log it all! - and use that to figure out your personal estimate. It's just more arithmetic, that's all. The above is simpler.

Any calculator (MFP or other), even a good fitness tracker worn 24x7, just give you the average calories for people similar to you on the few data points they know about you. The "12 x goal weight" type formulas just give a very generalized simple rule of thumb to roughly approximate more nuanced research-based formulas: Less likely to be accurate.

Use your own data. If you keep switching things up quickly, you'll never figure it out.

MFP, other good calculators, good fitness trackers: They tend to be close for most people, a bit high or low for a few, and surprisingly far off for a rare few. That's just the nature of statistical estimates.

MFP and my good brand/model fitness tracker are off by 25-30% in estimating my calorie needs, compared to nearly 8 years of MFP logging experience (loss then maintenance). Since MFP and the very same tracker produce close estimates for others who report here, it's not that those estimates are bad, it's that I'm statistically unusual in some way. (It may not be obvious why.)

The thing is, once I figured out my calorie needs based on experience data, my weight loss/maintenance became very predictable. That's why I'm suggesting this.

Best wishes!