If you can afford it, paid lessons are always more efficient and tailorable to your goals/preferences. Being at an appropriate level and then finding a language partner who is at a similar level to you is very important. Until a B1 level or so, language exchanges may put too much burden on your partner. If there is a strong mismatch between levels, this might lead to mostly speaking one language. This may be especially challenging for English native speakers as many people speak English at a B2-C1 level with this being further exacerbated by the ubiquity of exposure to the English language through the internet, TV shows, movies, music, university, etc.
Time zones and scheduling is also a challenge; another thing in favor of lessons as people have an incentive to talk with you in the middle of the work day in their country when you pay them! 😀