Pack recommendation for hiking and indefinite travel combined

A few months ago, I successfully completed a 3month backpacking trip across Southeast Asia with only my 32L Patagonia Black Hole pack as my carry-on bag and a 8L Patagonia lightweight sling bag as my personal item. Total weight hovered around 7,5 kg (17 lbs) and I never had issues with airline restrictions. I did find myself in cold weather at times, and I was wearing up to 4-5 layers when needed. I only brought two pairs of shoes - Saucony running shoes and flip flops. Literally no other pairs.

However, I've been thinking another round of travel and this time I'd like to go mainly to South America but also do the 14day Everest base camp trek - and that will inevitably require a pack with a waist belt, some decent back support and a bigger capacity because apart from my regular shoes, I will be also packing hiking shoes, a few more layers, a headlamp and other accessories needed for the trek at high altitude.

I've been eyeing the Osprey Farpoint 55 as it is a 15L daypack - perfect for daily out and about - along with a 40L main pack that is still carry-on compatible. I can use the daypack as a personal item when flying. My main worry is that this might still not be enough capacity given everything that I want to do with it, including the base camp trek. I'm hoping to keep the total weight below 10 kg (±22 lbs).

Does anyone have any suggestions? Would the Farpoint 55 suffice or do I really need to go beyond the 55L capacity and thus have the main pack as a checked bag?