AmEx Explorer v AmEx Velocity Platinum - Best Card to Book Reward Flights to UK

I'm debating whether to apply for either the AMEX explorer or the AMEX velocity platinum as a complete credit card / points beginner.

In particular, Im looking to fly to the UK from SYD once or twice per year ideally with Qatar.

I understand award seat availability is pretty good through Velocity compared to Qatar directly. Currently the platinum velocity gives you a sign up bonus of 120k velocity points whereas the explorer gives you 110k AMEX rewards points which can be converted to 55k avios.

For a business class one way flight to London its around 90k avios points or 139k velocity points.

I feel like having the velocity card and only having to earn another 19k velocity points to get the flight would be much easier than getting the 110k rewards points from the explorer, converting that to 55K avios, then having to earn another 70k AMEX rewards points to then convert to 35k avios to get a total of 90k avios for the flight.

I feel I might struggle to earn those extra 70k amex points or am I missing something obvious? Definitely like the idea of the AMEX points being a lot more flexible in who you can transfer to as an advantage

Any recommendations or advice? Cheers