From memory, Victoria to LCY in a black cab was around £50. You'd do Waterloo for about £40 traffic depending. Uber obviously cheaper than a black cab. And the cheapest I'd agree with others that DLR to Canning Town and then Jubilee to Waterloo. Suitcases really aren't an issue unless in morning rush hour and even then you'd be fine.
What time of day are you landing?