Understanding Points Value

I'm new to having a major travel credit card with reward point value. I'm trying to figure out to best utilize my points. Right now there's a promotion for purchasing a new apple product with an increase of 25% of points redeemed. This gives your points a 1.25 value correct? I see on TPG they currently rate chase ultimate rewards as 2.05 and recommend redeeming at any time for at least 1.5. I've been reading their articles and can't figure out how they've managed to get that evaluation. Can anyone explain this to me?

I ask for general information but also I'm looking to buy a new MacBook and then I'm also going to be flying mia to sea in a month. I'm trying to figure out the best way to use the points but it gets overwhelming and complicated quickly it seems.