the difference between a thinkpad T14 with replaceable RAM and SSD and a T14s with soldered RAM and SSD are minimal. depending on the specific generation and features, the T14s can be heavier than the T14.
i'd accept soldered RAM if it is at least 16GB, (though 32GB would be better) because i'd rarely need more than that. but a soldered SSD never. that holds my precious data, and even if i have a full backup, i do want to be able to take out the SSD when the laptop dies, or replace a broken or worn out SSD (as i had once). the risk of not being able to recover data from a soldered SSD is just not worth the few grams saved in weight.
The nice thing about picking up older laptops is that the upgraded models don't really hold as much extra value compared to what they cost new so if you keep looking you can get a pretty maxed out machine for not a lot more than the more common low-end ones.
a cloud backup for a 2TB disk is too expensive or to slow. an offline backup is not automatic and only current the moment i run it. a combination of both is more complex. an always synced full backup is difficult to achieve. it is possible when the only places where i use the laptop are at home and at the office. as soon as i add traveling and using expensive mobile data my backup becomes unreliable or to expensive to maintain or restore. in other words, even if i have a full backup, i can't always rely on it.
the data storage alone is not the issue. the cost of accessing that data is. not every place has unlimited fast internet that would allow you to download that much data without problems.
with a replaceable SSD i can (and in fact just did a few weeks ago) take the SSD from the old laptop and put it into the new one. took me 5 minutes.
restoring all that data from the cloud would have cost me a few hundred dollars in mobile data fees. or several weeks of visiting a restaurant which has free data, but would also have racked up a restaurant bill not to mention the time that would have been taken away from working.
With BackBlaze you can have them ship you your data on a hard drive. They charge you for the hard drive. But if you send the hard drive, they refund your money.
backblaze doesn't support linux or any kind of unix at all, which makes that a non-starter. and i could not find which countries they can ship to, but i am pretty sure they won't be able to ship to china without me having to pay import tax on the disk and cost of shipping back. and i wonder if they can even ship worldwide. i also have to install their proprietary software on my computer which means that despite encryption i have to trust them with my data. i'd rather not.
so sure, there are ways to get around the limitations of a soldered SSD, but so far i have not seen any that are worth the benefit of a few grams saved in the weight of my laptop. because that is what we are arguing about here.
backups are good, and everyone should have one, and they are certainly covering several failure modes regardless of whether the SSD is soldered or not. but an unsoldered SSD also covers a few failure modes that a backup doesn't cover. at the cost of a few grams of extra weight. my goal is to maximize the recovery options. so i have backups and a replaceable SSD.
the ultimate solution would be a laptop that supports two SSDs so i can run a raid mirror like my desktop. one of those SSDs could even be soldered in that case.
i do have a cloud backup. as i said the cost of that itself is not the issue. the cost of accessing it is. the raid protects against the "dead SSD" failure mode.
it's reliable in the sense that the data is there and won't get lost, and i can always access it to download bits and pieces if i need them. it is not reliable in the sense that i could always do a full restore from it without cost. having an unsoldered SSD reduces (but doesn't eliminate) the risk of me having to do a costly full restore from that backup.
i'd accept soldered RAM if it is at least 16GB, (though 32GB would be better) because i'd rarely need more than that. but a soldered SSD never. that holds my precious data, and even if i have a full backup, i do want to be able to take out the SSD when the laptop dies, or replace a broken or worn out SSD (as i had once). the risk of not being able to recover data from a soldered SSD is just not worth the few grams saved in weight.