It’s normal. You need not worry. Babies outgrow this. This is due to reflux due to immature sphincter or might be gag due to fingers . If baby is active, gaining weight well, not irritable, feeding well ,no abnormal posturing, soft abdomen you need not worry. Keep the baby burping in upright position for 20-30 min after feed. Feed in small quantities frequently and make sure position and latching while breast feeding is done in correct position. Putting fingers in mouth is a self soothing behaviour is a normal developmental pattern trying to explore their hands and help in oral muscles development. Only if it is interfering with feeding and if persisting vomiting you can share your concerns with paediatrician.

Greetings seems like normal infant reflux due to an immature digestive tract. Other possibilities include swallowing excess air during feeding or a mild gag reflex triggered by putting fingers in the mouth. Because your baby's weight gain is excellent, this behavior shares characteristics with benign, typical "happy spitting." To manage this, you can try keeping the baby upright for 20 to 30 minutes after every single feeding. Offering smaller, more frequent feedings and ensuring a deep latch to minimize air intake can also help reduce spit-ups.

Looks normal.

Hello! Spitting up milk is very common in babies below 6 months due to physiological reflux (GER). Your baby's weight gain from 2.8 kg to 6.56 kg is reassuring. My advice: Continue exclusive breastfeeding until 6 months. Burp your baby after every feed. Keep your baby upright for 20–30 minutes after feeding. Avoid overfeeding and excessive movement immediately after feeds. Always place your baby flat on his back for sleeping. Curd-like milk is normal, and putting fingers in the mouth is a common habit at this age. No medication is usually required if the baby is active, feeding well and gaining weight.

That's normal only it's because of Gastric reflex

Spitting up milk after feeds, even with burping, is very common at this age and usually isn't a concern if your baby is otherwise gaining weight well and seems comfortable. The curd-like look just means the milk has partly digested in the stomach. Putting fingers in the mouth around 4 to 5 months is often teething or self-soothing, not related to the spit-up.