You might check out the search feature on this site, cooling/overheating issues are a common posting with many tips on solutions. IMO, before getting too deep, look at the elementary things first. As you point out, a collapsing lower hose isn’t good. Getting a correct one is important, proper length and curve. You could insert a spring in it to prevent it from collapsing. This alone might be the problem.
Getting air out of the system that may be trapped is important. Air can get trapped when changing the coolant. Having replaced the lower hose, a lot of coolant in the block drained out. Good time to do a system flush, using a flush solution if you can do it; I use a back-flush connection, cheap at an auto store. Re-filling the system takes time necessitating adding more coolant, once the t-stat opens the radiator will drain down needing to add more. Don’t overfill the radiator during the process or you’ll get a mess. When I know it’s getting near to full, I use a 32oz wide-mouth milk or soda bottle with the bottom cut off for filling, if air is trapped it will cause some purging of coolant up into the bottle and may settle back down if you haven't put too much in.
Checking for water flow you can observe it by giving some slight throttle, too much and likely coolant will puke out. Flow will be noticeable under slight throttle. If the pump is faulty, typically it will make sporadic ticking or rattling noise, or leaking from the weep-hole, and another check with engine off is to see if there is fore-aft play with the fan. Full coolant should be an inch or so under the opening, not up to it.
Ok, basic info, but don’t know what experience you have, so pardon if I’ve insulted your know how.
