I would say upgrade to the 14-inch M3 Pro MacBook Pro since you’re upgrading from an Intel machine, which the higher end M-series processors/models replace, not the lower end models, for example; only the higher end models have two fans, they support multiple external displays, and have three Thunderbolt 4 ports (I’m comparing the lower end base 14-inch M3 model to the higher end models with the M3 Pro/Max chips).

It all depends on your needs and/or budget, but if you were to upgrade the storage on the base 14-inch M3 model, it would be near the price of the higher end M3 model with the M3 Pro chip, which would be more worth it to upgrade to.

If you’re on a budget, maybe opt for the 14-inch M2 Pro MacBook Pro since Best Buy has a Black Friday sale on it, which would be more worth it than the base M3 model, but if you’re not then I would say go for the M3 Pro 14-inch MacBook Pro.

Best Buy also has the higher-end M3 Pro models on sale too with certain storage, memory (RAM, and chip configurations. As a tip, you should get AppleCare+ yearly too.

Here are some links if you wanna check out some of the best sales that Best Buy has for the new models.

As a tip, I would prioritize memory (RAM) over storage since you said that you use external hard drives (I recommend Samsung T7 SSDs) but it’s always a good idea to upgrade the storage just in case, though 512 GB should be enough especially if you’re using external hard drives for your Final Cut Pro libraries.

I know this might seem like a lot but I hope it helps you understand it a little easier.

Direct search link:

https://www.bestbuy.com/site/searchpage.jsp?id=pcat17071&qp=category_facet%3DMacBooks~pcmcat247400050001^modelfamily_facet%3DModel Family~Apple MacBook Pro^systemmemoryram_facet%3DRAM~18 gigabytes^systemmemoryram_facet%3DRAM~16 gigabytes^systemmemoryram_facet%3DRAM~36 gigabytes^systemmemoryram_facet%3DRAM~48 gigabytes&st=m3+pro+macbook+pro

Some links I found:

https://www.bestbuy.com/site/apple-macbook-pro-14-laptop-m3-pro-chip-18gb-memory-14-core-gpu-512gb-ssd-latest-model-space-black/6534615.p?skuId=6534615

https://www.bestbuy.com/site/apple-macbook-pro-14-laptop-m3-pro-chip-18gb-memory-18-core-gpu-1tb-ssd-latest-model-space-black/6534624.p?skuId=6534624

https://www.bestbuy.com/site/apple-macbook-pro-16-laptop-m3-pro-chip-36gb-memory-18-core-gpu-512gb-ssd-latest-model-space-black/6534625.p?skuId=6534625

https://www.bestbuy.com/site/apple-macbook-pro-14-laptop-m3-max-chip-36gb-memory-30-core-gpu-1tb-ssd-latest-model-space-black/6534620.p?skuId=6534620

https://www.bestbuy.com/site/apple-macbook-pro-14-laptop-m2-pro-chip-16gb-memory-512gb-ssd-space-gray/6455369.p?skuId=6455369

Let me know if you have any questions.