Spongy brake pedal

Good day, have a question regarding my truck listed above double cab. I've owned this vehicle for 4 years. A year ago, I had changed rear brake shoes and adjusted them correctly but had issues with parking brake. Took it to a local (chico ca) Toyota/Lexus specialized shop and I was informed the brake fluid was old, it apparently had 4% moisture in it (so system was flushed, refilled, and bled), after I got it from the shop the brakes and parking brake were phenomenal I mean "absolutely perfect".
Brake pedal was solid and hardly had to depress it, brakes I could tell were grabbing at all corners felt like a sports car. The parking brake hardly went down upon depressing the pedal. Fast forward year later pedal is soft again I adjusted the parking brake and can tell it's grabbing (not as good as after the shop but grabbing), the brake pedal however is soft as it was before it took it to the shop and I know it's not supposed to be like that. My question is, what process do you guys normally do to eliminate that soft pedal on these trucks to get the brake pedal back to where it was when I had gotten it back from the shop I took it too? Is bleeding the lspv a consistent necessity upon readjusting the rear shoes and parking brake to get everything back and sync'd up? I love my truck but this issues pretty irritating and don't want to have to pay a dang shop every time the brakes need to be adjusted. I've been working on cars (I'm 42 now) and I've never had this issue with vehicles and brakes. I mean I've owned vehicles such as '64 Mustang, '67 Skylark, '56 n '66 Chevrolet trucks, and a '67 Pontiac Le Mans which all had 4-wheel drums. Why is it these trucks braking system seemingly is such a pain to get it where it's supposed to be? Any help from your experience would be majorly helpful. I know you get inundated with these, but it'd be great to get an insight on this truck's "quirks". Thanks guys have a great weekend.


Rob