By using a 3 way splitter rather than a 4 way splitter you should get back some of the signal which may help if the signal level is just marginal with a 4 way splitter.

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Code:
https://www.ebay.co.uk/p/F-type-Screw-Connector-Splitter-for-Virgin-Cable-5-2450-MHz-3-Way-Bt04/1137760162?iid=261778665293

It may also be beneficial to correctly terminate any unused splitter outputs. It will not however make any difference if the signal is too low.

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Code:
https://www.ebay.co.uk/itm/05302-10x-F-type-Male-Plug-Terminator-End-75-Ohm-Connectors-for-F-type-Socket/271116694395?hash=item3f1fd0737b:g:XOEAAMXQBg5RsIJy