If you're unfamiliar with working on brake hydraulics, please seek professional advice from a good independent Euro mechanic. They've been worth their weight in gold to me over the years. I'm not bragging here: I have decades of experience with makes & models from the 70s through the teens, a very nicely outfitted man-cave, and I'll still take cars to my mechanic for jobs I'm unfamiliar with.
Anyhow...it seems to me that your ABS system is working as designed. I'd suspect another problem. if your brake pedal is super stiff, I'd check for a seized caliper or air in the brake lines. My brake pedal is pretty tight but not nearly as bad as yours.
I'm not trying to be pedantic here, just trying to figure out your mechanical skill & familiarity:
How old is the brake fluid?
Brake lines looked OK? No cracking in rubber hoses nor rust on hard lines?
How did you bleed the system?
Is there any possibility of debris in the master cylinder?
Were the caliper pistons difficult to retract on the last brake job?
Are the brake pad rails and caliper slide pins lubed properly?
Does the brake booster groan or chatter?
New calipers can be pricey, but they're easy to rebuild if you're handy. RockAuto has a decent selection of cheap rebuilt calipers. Centrics have worked OK for me. PM me for a discount code.
Those break pad lights have been unreliable for me. Mine always have problems. I've done a lot of work to turn off that stupid dash light but it seems to break again every year or so. It's on right now!