I listened to a lot of podcasts which discussed, or better, analyzed the problem of learning two (or even three) languages at the same time. All of them incline toward the idea that it is possible; some of them even support the opinion that it has advantages — the learning processes would support each other.
The differences between the speakers exist regarding the question of how to put it into practice and what should be avoided. A very young guy recommended splitting your personality, or better, creating different personalities with which the languages are associated. Others prefer to use different locations or situations for each language they deal with: French in a café, Italian in a kitchen, and so on.
Everyone seems to agree on the opinion that it is preferable to learn from different levels. If you start at the same level, you should make sure to give language A priority first, then bring B up to the same level, then again focus on A, and so on.
And all of them agree on not learning similar languages at the same time, except when one of them is already at a high level, e.g., C1 or higher. Examples of such situations are German and Dutch, Italian and Spanish, Russian and Ukrainian.