PLEASE HELP!!! my macbook pro charges slower and doesn't hold a charge as long WITH apple replaced battery

This has been an ongoing issue for me. Recently, I had my battery replaced by apple, so this is not a battery issue. Both before and after the replacement, the battery only lasts around 3-4 hours with normal web browsing, low brightness, etc. Nothing suspicious on the CPU either. Also, I've noticed it often takes a long time to charge. Not anything crazy like 20 hours like some of the questions I've seen on here, but for example, only around 30% or so in a little over an hour. I'd say it takes around 3 and a half hours to charge fully. I don't remember it being quite that long previously.

I've tried switching outlets and chargers too (don't worry, I use an apple brand), resetting the SMC/PRAM and I'm running the latest software version. I had the full diagnostic test done by the geniuses and my computer totally passed.

Is it possible that since my computer is just older (nearing 5 years) that it simply can't function any better than that? I have been going crazy trying to find answers here and if this is the case I'll just suck it up until I get a new one next year. I need it for school which makes this annoying, but I can always just sit near outlets, and I also have a portable battery charger (Lizone) that we just ordered so that will help too.

PLEASE, ANY input on this would be so helpful. The geniuses have basically had me spinning in circles, trying things in "Safe boot" to see if it helped the battery (it didn't) and just offering weird roundabout solutions. Nothing helps. Even if you don't have advice on how to fix it, if anyone has seen this before in older computers and knows it is just something that happens, then that will be useful to know!!

Thanks so much for your time and to anyone wh