Wanderloop

One of the visions of joblib is to avoid computing the same thing twice. Joblib proved pretty useful to me while doing ML @Wanderloop. Joblib saves your entire sklearn pipeline in .joblib file format that can be reused by uploading the file to the session and obviously a one-line code snippet. It comes in handy when different models produce desired results with the same hyperparameters.

MySQL 8.0 is significantly better than MySQL 5.7. For all InnoDB row operations, you'll see a great performance improvement. Also, the time taken to process transactions is lower in MySQL 8.0. Moreover, there has been an improvement in managing read and read/write workloads.

Since you are trying to make a Roblox game, you have no other option than to use Lua, since Roblox only allows coding in Lua. Yes, you've heard right, Python is identical and as easy as Lua, although Lua is easier than Python. Beginning from Lua and then escalating to Python is recommended. Java is only helpful when you are creating a heavy, big-budget, enterprise-level product, otherwise, Python would suffice.

I would recommend a mixture of MySQL and MongoDB. Using MongoDB for the Content Distribution Network (CDN) will make it easy to store high volume incoming data. MySQL is recommended to be used for business logic. PostgreSQL is not recommended since you will be faced with inefficient database replication features and constant migration from one PostgreSQL version to another.

If you are looking for more functionalities for free, Jira should be your go-to solution. The free plan of Jira includes a user limit of up to 10 users, scrum and kanban boards, backlog, agile reporting, customizable roadmaps, 2 GB media storage, etc.

While on the other hand, Zenkit's free plan includes a user limit of up to 3 users and 1 GB media storage, etc. Gantt chart feature isn't available in the free version.

While Github does provide the facility to store packaged software under Github Package Registry, it comes with fewer integrations. JFrog Artifactory comes with more integrations (other than npm, Docker, Maven, NuGet, Maven, Gradle, and Swift, which are also integrated with GPR). Artifactory also provides on-prem and hybrid options for packages that Github does not.

Rule out PHP since you aren't familiar with it, and learning it would take much time since PHP has turned out to be complex lately.

Node.js vs. Flask

Node.js is your go-to solution for developing speed-intensive websites and applications (eCommerce stores, chatbots, etc.). Flask isn't the ideal solution. Django (another Python-based web framework) is better than Flask.