Calories and Maintenance

4 kg to go should be minimum deficit - 250 cal would be reasonable.

If it had been bigger deficit and rate of loss had been more - body likely stressed out, workouts not as good as you think.
While body is in a stressed state, workouts will indeed feel hard, indeed may be giving it all you can.
But that "all you can" is at a reduced rate compared to what it could be.

Measuring normally means by volume, which in metric isn't that bad for some items - but calories is per gram weight, not volume mL.

So perhaps review the types of items you eat that are done by volume if that's what you meant. If high calorie or fat, errors there can add up.

You mentioned HR while lifting, if that means you have a calorie burn for that which is based on HR calculations - it's inflated.
Are these body weight resistance routines, or with weights and sets & reps and rests?

Do you indeed measure several spots already, to see if inches have been lost.

Betting anything you attempt less deficit, you'll see workouts improve, and progress.

10K steps is well beyond sedentary if that is mainly outside of exercise.

When the body is asked to loose too fast a rate for the amount of fat left - it will get stressed.

Shoot, make it bad enough and even the fact of doing resistance training and eating enough protein doesn't mean you won't lose muscle mass.
The aggravation of natural body builders for show prep, trying to cut fat.

But that type of stress increases cortisol - increased water weight.
Inches will still be lost - but it's a terrible state for the body to be in, while trying to lose weight. Shoot, in general for the workouts too.

By that point the body as already adapted other things to lower it's calorie burn, if that didn't help enough, worse things happen.
None of those things stop fat loss - you can always eat less and stress water weight will top out, muscle mass along with fat can be lost - yes, you can get the number of the scale moving again.

And frankly people that do that are in an extreme diet, and they are the ones repeating the routine again next year because they failed to reach goal weight or maintain it, and discover it's much harder and they don't know why the next time.

Down at the final pounds and desiring to have good body composition too - many ways to get the last few off.

Studies have shown a week on/week off diet are great for allowing hormones to get back to where they need.
That routine may actually allow being slightly unreasonable on deficit, but because it's just a week and you go back to maintenance - not near the stress. Plus only a couple of tough workouts on diet week.

Studies have shown the 5:2 diet, with 5 days at maintenance, and 2 days at 25% of maintenance, allow the same thing for the body to recover. I could never fit it in well with resistance training and evening workouts - body wanted the food for repair in next 24 hrs - during the time I would be eating barely anything - made the next workout pretty bad with recovery not done.

Then just taking that 250 cal deficit, after perhaps a couple weeks of eating at maintenance.


Since you mentioned steps - what are you using providing that?

Think about which method might work for best for your mentality and workout and schedule.
And would you prefer to eat the same amount daily no matter what (except on the 5:2 method) - TDEE deficit style, or varying amount daily depending on what you've done - MFP style?

Since you don't mind eating the same daily no matter the activity level, you might do well enough with the TDEE deficit method (which includes exercise). Instead of MFP's NEAT method (where you add exercise when actually done).
Because if you aren't accounting for exercise - you are making the deficit bigger and worse.

TDEE method - Weekly activity level averaged out to a daily level - eat the same daily.

Maintenance or deficit, doesn't matter.

Use this:
Just TDEE Please spreadsheet - better than rough 5 level TDEE charts from 1919 study.
https://docs.google.com/spreadsheets/d/1G7FgNzPq3v5WMjDtH0n93LXSMRY_hjmzNTMJb3aZSxM/edit?usp=sharing

10K steps is a lot of steps, no where near sedentary.
So if you have no estimate of time walking to get those steps (you didn't mention what is giving you a step count - this may be a whole lot easier depending on what that is), then activity level is almost the highest where I put it.
I will say when I did that, the sheet didn't update the figures in my view for some reason, using Chrome, so not sure what's stuck.
It initially went lower when I deleted prior "x", but it didn't go back up, so I know the formulas are working.
Perhaps it's just my add-ons or such blocking updates on Chrome.