Depending on budget it can be a great option. I suggest pricing out what it would cost to upgrade the pieces on the existing motherboard vs what it would cost to build something in the current models with a new motherboard. At the end you will end up with better classes of parts from 2018 but they will still be older and lacking in the efficiencies of newer.

Personally over the past few years I would recommend looking into a newer model AMD Ryzen system. Look into a motherboard from a couple years ago that supports the current gen CPU socket and DDR5 to set yourself up for the future. Get yourself an NVMe M.2 SSD and a Ryzen 5 with 32 GB of DDR5 and you would notice a huge difference and have great upgrade potential with current gen parts.

This all depends heavily on your budget however. Use a site like PC part picker to through all the parts for a few builds in and see which fits comfortably in your budget just recognizing that depending when you plan for your next upgrade, the only thing you could take from maxing out your old system would be the SSD.

What he means is to upgrade to the highest version of parts that your motherboard will support. So as an example, figure out the highest model i7 that will fit your chipset and socket and look into that. Because it is older it won’t have the premium price a new model will have but would still be a considerable upgrade for you. This upgrade would replace your CPU, RAM, Storage, and if you can afford it then GPU. You can do them in stages to save money as well in which case I would recommend this order, Storage > CPU > RAM > GPU.