For research, I always recommend starting simple with Excel to get familiar with numbers and stats. Python IMO should be the next step. I wouldn't execute with either one. IMO they're best suited for prototyping.
Random thoughts, If you are going to use python, Dr. Howard Bandy has some good books that include python code (and AmiBroker code). I have no interest in using python. I use Java and will eventually move to Kotlin (a JVM language). That said, C# is a great choice since many platforms use it. Ninja, MultiCharts.net, Wealth Lab Pro, others? Python is a good choice to cobble things together and/or if your platform of choice uses it. Java and C# are good if writing high-performance professional applications. I would pick platforms/languages that have lots of example code available for free. I like the idea of being able to download the code in Stocks & Commodities mag and load it into a platform and see what it does. I've never programmed Excel or MATLAB so I can't comment. Have fun
It all depends on what you are great at and the tasks you wanna undertake, but you could use any language to implementing things in algotrading, though there are other tasks that would require you to use high level language like C++, to solve the problems at hand. So the kind of language you use, is dependent on you entirely.
python and the pycharm IDE . lots of examples out there on youtube and stackoverflow. tons of data functions
And if you are a trading system developer, Prof. Bandy's website (Blue Owl Press) has a number of excellent (and free) videos, articles and other resources. Highly recommended.
Another book I would recommend is from Yves Hilpisch it's dedicated to Python application for finance and serves as a good introduction in programming trading strategies.