2017 imac with fusion drive running high sierra is it worth upgrading to newer OS?

I have not upgraded and wondering on this computer if it is worth doing so. As of now it seems to always be lagging with even simple tasks such as browsing multiple web pages and it can be frustrating. I understand the fusion drives on these are the weak point. Are there any options for making this a bit more tolerable such as upgrading the OS or will the newer OS just make it worse?