1.5L is overkill for the use case you have. Pick any current gen i5 or ryzen 5, a compatible motherboard and ram, slap it in a case you like, you're good to go. It's hard to predict what hardware and software will be like a decade from now but for your basic browsing/office tasks and movies etc, even a mid range current gen cpu will last a long long time.
Another option is a mini pc or thin client but personally I'd say avoid that because they'd reach end of life within a few years and being proprietary systems you'd not be able to buy off the shelf replacements for anything that fails.
