Moving from FinTech to Finance early-on in career

Hey WSO, Im in need of some advice. Just some background info:

I graduated last year with a computer science degree and joined a graduate programme on a sell-side company. I'm still getting my bearing in London's financial tech scene. I will soon complete my graduate programme (where I tried different roles Quant Asset Management, Trade Ops, etc...). The programme is almost over, and soon I'll have to choose a team I want to join. The two teams so far with the most prospect that want me back are a Data Science team (as a junior data scientist) and the Electronic Trading (HFT) team (on a Trade Ops role). For me this sets two paths, which either tend toward tech, with Data Science, or towards finance, with Trade ops in HFT.

Now, in my view, if I'm going to work in Finance, I'd want to work on the business side. The people that work there are the one generating the value, so they are obviously the ones with better career prospects and salaries. If I was to work for a FinTech company, I would want to fit in on the Tech side, but not as a developer.

Thus I see a few paths I could take here:

1. To work in data science: Take the data science role, and specialise in that area. This will give me the opportunity to work in almost any sector, while making a decent. However, salaries on non-management position cap generally at under 200K, which is below my long-term financial goal.
2. To work in FinTech: Pursure the Trade Ops role on the HFT desk. This seems like it would give me a good balance between having the ability to either stay on the Tech side, or move lateraly to a front-office role, with enough experience. What I am worried about here is getting stuck in Trade Ops, and not been able to move out of the role.
3. To work in finance in IB/Corporate Banking: Honestly I have no idea here. The only possible route I could see to this is in parallel with the one above, where after having worked with an Electronic Trading team, I shift into an analyst role modelling out LBOs etc.... This will likely take place in my mid/late 20s, so this might not be realisable at this point

Moving away from my assumption, I have a few questions I need counsel on:

1. What are some general career prospects for the two roles mentionned above (Trade Ops, Data Science in banks)?

2. On the buy-side whether it is for a hedgefund, VC or PE firm, what are some career prospects working for a Fintech firm vs purely financial service firm (quality of life, salaries, etc...)?

   1. What is a path I could take from where I am now to work in a financial service buy-side firm on the business side?

   2. What is a path I could take from where I am now to joining a fintech buy-side firm on the tech side?

3. How much experience can I realistically gain on a Trade Support role in HFT and what are the possibilities of moving to the Buy-side with this experience?

4. Have you seen people moving from Data Science (in banks) or Trade Ops into Investment Banking?

Any other thought/pointers you could give me about the roles above would be really appreciated